
Class _§_£l3A 
Bnnk ' C *C6 

Copyright N° 

COFVR1GHT DEPOSIT 



Science of 
Threshing 



Treating the Operation, 
Management and Care 
of Threshing Machinery 

BY G. F. CONNER 



REVISED EDITION 



PUBLISHED BY 

The Threshermen's Review Company 
ST. JOSEPH, MICHIGAN 



LIBRARY of CONGRESS 
Two Copies Received 

MAR 1906 

_ Copyrizht Entry 
CLASS <X XXc. No, 

\ M- ° °f 

COPY B. 



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Copyright 1906 

The Threshermen's Review Company 

All Rights Reserved 



PREFACE. 



In no other line of industry has the present genera- 
tion witnessed so marked a degree of development 
as in the design and manufacture of grain handling 
machinery. When we consider the difficulties to be 
encountered and the obstacles to be overcome in 
taking heads of grain, husking the minute kernels 
. from the covering, afterwards known as chaff, in 
which Nature has enveloped them, depositing the 
golden grain in the sack, and delivering the refuse 
according to the will of the operator in so perfect and 
expeditious a manner, we may look upon the modern 
thresher as a marvel of success. 

To the thresherman in the field belongs more credit 
for this achievement than is generally accorded him. 
He is the final dictator. On his judgment a device 
must stand or fall. His is the part to suggest, the 
manufacturer's to execute. And even now, face to 
face with the proficiency already attained, we find 
that there is room for more and deeper study. 
Further progress can be made by all working in 
unison. 

By some the position is taken that there can be 
formulated no definite rule by which to operate a 
machine, and this is true to a certain extent. The 
same may be said with equal truthfulness of any work 
requiring skill, as skill can be had only by experience. 
Each and every part of a threshing outfit, from the 
foot board of an engine to the tail end of the straw 



carrier, works under and obeys some law peculiar to 
itself. Unless both manufacturer and operator under- 
stand the various laws and principles which govern a 
device, it is liable to fail to perform the functions 
intended, though both parties may have had unlimited 
experience. This necessary understanding or knowl- 
edge can be gained much more easily and successfully 
than by depending upon the slow process of the 
school of experience to educate and teach what 
should have been understood at the beginning. As 
the mind will grasp information from any source 
within reach, the written rule is much the better 
method by which to gain a knowledge of the laws 
and principles. The mind must first be informed and 
then the hands made skillful. Recognizing this, the 
author has endeavored to place before the reader 
such an exposition of the subject under consideration 
as will best enable him to reap the best results from 
his labor. 

If this book is the means of aiding anyone in his 
part of the work, the author will feel conscious of 
being well repaid for the labor and time consumed 
in preparing it. 

Due acknowledgement is hereby extended to all 
who have aided in any way to make it a success. 

George F. Conner. 



Table of Contents. 

PART I. 
CHAPTER I. 

THRESHING. 9 

CHAPTER II. 

THE SEPARATOR. 
The Threshing Members — Cylinder, Cylinder 
Teeth, Concave, Grate, Feed Board 14 

CHAPTER III. 

THE THRESHING MEMBERS. 

Beater, Check Board. The Separating De- 
vices — The Rack, Raddles, Combination of 
Rack and Raddle 23 

CHAPTER IV. 

THE GRAIN CLEANING MEMBERS. 

Sieves, Fan, Blast, Sieve Motion 32 

CHAPTER V. 

THE DELIVERY MEMBERS. 

Stackers, Weighers, Measures, etc 40 

CHAPTER VI. 

FEEDING. 
Uniform, Irregular, Self Feeders 43 

CHAPTER VII. 

OPERATION. 
Weather and Grain Conditions, Cracking Grain, 
Various Kinds of Grain 47 



CHAPTER VIII. 

THE BLAST. 

Relation to Shoe, Effect, Proper Strength, 
Sieves 55 

CHAPTER IX. 

BELTS. 

Care and Management, Adjustment, Lacing. ... 64 
CHAPTER X. 

BABBITTING BOXES. 

Babbitt Metal, Directions 68 

CHAPTER XL 

LUBRICATION. 

Selection of Lubricants, Cylinder Oils, Hard 
Oils, Getting Ready 70 

CHAPTER XII. 

THE CREW. 

Manager's Duty, Feeders, Band Cutters, Pitch- 
ers, Straw Crew 74 

CHAPTER XIII. 

WASTING GRAIN. 

Losses Easily Over-estimated, No Waste Impos- 
sible, Reasonable Waste 78 

PART II. 

TRACTION AND PORTABLE ENGINES. 

CHAPTER I. 

HEAT. 

General Theory, Generation of Steam, Temper- 
ature 83 



CHAPTER II. 

LATENT HEAT. 

Definition, Energy, British Thermal Unit 87 

CHAPTER III. 

COMBUSTION OF COAL. 

Chemical Combustion, Distillation, Fuel Values, 
Evaporative Power, Heat Conducting Power 91 

CHAPTER IV. 

PROPERTIES OF STEAM. 95 

CHAPTER V. 

SATURATED STEAM AND ITS PROPERTIES. 

Heat of Liquid, Latent Heat, Total Heat, Spe- 
cific Volume, Density, Steam Tables 96 

CHAPTER VI. 

THE BOILER. 

Locomotive, Return Flue, Vertical 103 

CHAPTER VII. 

BOILER FEEDERS. 

Atmospheric Pressure, Pumps, Injectors 106 

CHAPTER VIII. 

BOILER PARTS. 

Fusible Plug, Grate, Safety Valve, Steam Gauge 1 1 1 
CHAPTER IX. 

CARE OF THE BOILER. 

Examination, Steaming Up, Cleanliness, Foam- 
ing 114 

CHAPTER X. 

FIRING. 
Regularity, Fire Depth, Ash Pit 118 



CHAPTER XL 

THE MECHANISM OF THE STEAM ENGINE. 

Cylinder, Eccentric, Slide Valve, Governor, 
Speed Changer 121 

CHAPTER XII. 

SETTING THE VALVE. 

With Remarks on the Traction Gear and the 
Traction or Drive Wheels 134 

CHAPTER XIII. 

WHISTLE SIGNALS. 

Some Poor Practice, Proper Code 138 

CHAPTER XIV. 

OPERATING AND HANDLING OF THE ENGINE. 

Starting, On the Road, Guiding, The Friction 
Clutch, Gear Lock, Setting 141 

CHAPTER XV. 

TESTS FOR LEAKS. 1 47 

CHAPTER XVI. 

FRICTION AND LUBRICATION. 150 

CHAPTER XVII. 

WINTER CARE OF THE ENGINE. I 53 

CHAPTER XVIII. 



SEPARATOR AND ENGINE DONT S. I 54 

CHAPTER XIX. 

A SUGGESTION. 157 



Science of Threshing 



CHAPTER I. 

THRESHING 

Threshing is the process of removing the kernel or 
grain or seed from the stalk to which it is attached. 
The ordinary threshing machine of to-day is able to 
operate successfully on wheat, rye, oats, barley, rice, 
flax, timothy, millet, buckwheat and peas. 

These plants carry the grain or seed in a head, each 
kernel being surrounded and held in place by a 
covering or hull. Threshing is the removing of the 
kernels uncrushed or unbroken from this covering, 
free from dust, dirt and other parts of the plant. 
These parts, when removed, form the so-called chaff. 

Naturally, the first step in the process of threshing 
is to loosen the hard kernel from the head. This is 
most easily done by striking the head. In Biblical 
times, even now in the far East, this pounding or 
striking was done by spreading the unthreshed grain 



10 SCIENCE OF THRESHING. 

upon a prepared threshing floor and driving horses 
or cattle over it, the hoof as it came down upon the 
head splitting open the hull, or seed pod, and forcing 
out the kernel. 




Later this result was accomplished by the flail, 
which is nothing more or less than a mallet having a 
long handle which enables the riser to stand fairly 
erect, the loosely hung long head of the mailer 
striking a quick, sharp, rebounding blow, which 
produces a jarring shock and causes the kernels to 
fly out. 

With the present plan of threshing, the grain is 



SCIENCE OF THRESHING. II 

struck in a manner similar to the flail, by the rapidly 
moving teeth of the cylinder as it revolves. The 
action of the flail is increased many times by the 
increased number of teeth and the greater speed at 
which they travel. Stationary teeth in the concave 
retard and hold the grain in place while being acted 
on by the cylinder teeth. The "concave" teeth are 



-/ 



pBflHHal II 9m 




arranged so the cylinder teeth can pass between them. 
The unthreshed grain heads are laid on the teeth of 
the concave, and the cylinder teeth strike them quick, 
sharp blows. The tendency of the heads to bound 
back from the teeth forces the kernels out from the 
hulls, already split by the contact with the teeth. 
Thus it is seen that the cylinder, with its teeth, 



12 



SCIENCE OF THRESHING. 



and the concave with its teeth, are the parts of the 
modern threshing machine which perform the work 
of the horses' hoof of ancient days and the flails of 
more recent years. 

After the grain had been stamped or beaten out on 
the threshing floor, the heavy berries were separated 




from the straw by careful raking, and from the 
chaff by tossing in the air, the wind blowing the 
lighter refuse away. Or else air was forced through 
the grain — as it fell in a thin stream — by a fanning 
blanket. Later, the fanning mill was invented to 
both sift and blow out the chaff. 



SCIENCE OF THRESHING. 1 3 

To-day the separator performs the task of raking 
the straw and sifting and fanning the grain. In 
addition, il delivers the grain in one place and 
removes the straw and chaff to another. It performs 
these widely different steps by, 

First. — Loosening the kernels from the heads. 

Second. — Separating the kernels from the straw. 

Third. — Removing the chaff. 

Fourth. — Delivering the grain and straw in sepa- 
rate places. 



CHAPTER II. 
THE SEPARATOR 

While varying in minor details the modern 
thresher consists of — 

First. — The threshing members — the cylinder and 
concave, with their teeth, the grate and the feed 
board. 

Second. — The separating members, which separate 
the loosened grain from the straw — the beater, 
check-board, racks or raddles. 

Third. — The cleaning members which remove the 
chaff and dirt — the cleaning mill or shoe, and screens. 

Fourth. — The delivery members which carry the 
grain in one way and the straw in another — the grain 
spout, tailings elevator and straw carrier. 

THE THRESHING MEMBERS 

CYLINDER. 

A cylinder consists of a number of parallel bars 

fastened to the peri- 
pheries or margins 
. of circular discs, 

spiders, or heads by 
means of bands 
shrunk around them, 
the whole being 
mounted on a suita- 
b 1 e shaft. The 
14 




CYLINDER 



SCIENCE OF THRESHING. 1 5 

cylinder teeth are inserted in sockets in the bars, and 
are secured by nuts on the inside, or by wedges. The 
cylinder should be capable of endwise adjustment so 
that its teeth may be made to run centrally between 
the teeth of the concave. The cylinder acts as a 
balance wheel in which is stored power to maintain 
its speed when an undue amount of straw is permitted 
to enter. There are usually nine or twelve bars in 
the cylinder. 

As hitherto indicated, the office of the cylinder is 
to loosen the kernels from the head. This is accom- 
plished by the cylinder tooth striking the unthreshed 
head with sufficient force to jar the kernels loose from 
their retaining hulls. Therefore the cylinder should 
run with sufficient speed to entirely free all the 
kernels and not leave any on the straw. If for any 
reason the cylinder does not do its work thoroughly, 
the result is wasted grain. In some instances some 
of the kernels will be partially loosened, but adhere 
to the head until nearly through the machine, when 
they will fall out and be carried along with the straw 
to the straw stack, thus making the machine appear 
to be at fault in separation by wasting the grain, 
when in reality the threshing members are not doing 
their work properly. The usual speed of ordinary 
cylinder teeth is about 6,000 ft. per minute. Under 
ordinary circumstances, this will thoroughly dislodge 
the kernels, if the teeth be brought in contact prop- 
erly with the heads. In dry, brittle grain, a slower 
speed may often be used by running the machine 



1 6 SCIENCE OF THRESHING. 

slower which will thoroughly dislodge the kernels 
and not break the straw so badly. In damp and 
tough grain a faster speed may be used if necessary 
to thresh the straw clear of kernels. 

On account of the cylinder being so heavy and run- 
ning at so fast a speed, it should be kept in perfect 
balance, as it greatly adds to the smooth running of 
the machine. When the cylinder is out of balance, it 
is easily detected by the jarring or vibrations in its 
vicinity. By placing the hand upon the frame work 
of the machine near the cylinder boxes or bearings, a 
peculiar jarring may be plainly felt when the cylinder 
is not true. The side on which this is most evident 
will indicate the end of the cylinder which is at fault. 

If permitted to run out of balance, the cylinder 
will have a tendency to cause its journals to heat and 
wear out rapidly, and also to flatten the cylinder shaft 
on the side that receives the wearing strain. A 
smoothly running cylinder requires a minimum of 
power to drive it, as whatever force is used to cause 
the vibration is so much power lost, or work done for 
nothing. The working and lasting qualities are also 
lessened, if allowed to vibrate, as every vibration has 
a tendency to loosen the framework of the entire 
separator. 

A cylinder may be put in balance by removing it 
and placing it with its journals resting on two parallel 
straight edges, such as carpenters' squares set up 
edgewise. The squares or straight edges should first 
be trued up with a spirit level, and may be held in 



SCIENCE OF THRESHING. 1 7 

place on edge by driving spikes on either side of 
them. The cylinder will adjust itself by turning on 
the straight edges, the heavier side going down. 
Wedges or pieces of iron of the right weight should 
be driven in between the band and head on the light 
side of the cylinder to cause it to balance or remain 
without turning in any position in which it may be 
placed. 

If cylinders are properly balanced when they come 
from the shop, this method will usually put them in 
good running order. However, a cylinder may seem 
to be in good balance when on the straight edges, 
and not so when in motion in the machine, the cause 
being that one end is heavy on one side while the 
other end is heavy on the opposite side. In such 
event, the cylinder should be run rapidly in loose 
boxes, and while in motion a piece of chalk should 
be held steadily near enough the shaft at the journal 
to mark it slightly. The chalk will strike and mark 
the heavy side, and the balancing piece should be 
inserted as before, both ends being correspondingly 

trued. 

A cylinder is sometimes thrown out of balance by 
putting in some new teeth irregularly around the 
cylinder, leaving part of the old ones in. In this 
case, the remedy is to replace all the old teeth, when 
much worn, by new ones, thereby redistributing the 
weight in an even manner. 

It will aid the cylinder greatly to work freely and 
easily if the separator stands still on its trucks while 
in operation. 



I 8 SCIENCE OF THRESHING. 



CYLINDER TEETH. 



The cylinder teeth are made so as to be easily 
replaced when worn out. The forward side of each 
tooth is curved slightly. 

If perfectly straight, it has a tendency to carry the 
straw into the machine too rapidly. On the other 
hand, if worn too much it retards the passage of the 
straw into the machine, thereby interfering with the 
feeding. The cylinder should be adjusted so the 
teeth will pass midway between the teeth of the 
concave. If permitted to have too much side play, 
or to run too close to the concave teeth, the teeth will 
crack the grain and chop the straw up, and at the 
same time, will permit heads of grain to pass 
unthreshed through the wide openings which occur 
opposite the narrow intervals. The teeth sometimes 
become loose and cause delay. This is especially 
true of new teeth when first inserted, as they do not 
always fit perfectly, and the strain to which they are 
subjected when the straw becomes compressed in 
moving through, makes them move a little in the 
bars. Accordingly, new teeth should be watched 
carefully when first inserted and tightened up until 
they are well seated, when they will stay in place. 
Much time will be saved by going over the cylinder 
each day and tightening up the new teeth. Many 
devices have been used to keep the nuts from working 
loose, some of which have considerable merit. 
Wooden bars have been used inside of the cylinder, 
the natural spring of the wood permitting the teeth 



SCIENCE OF THRESHING. 19 

to yield a little without becoming loose. A twisted 
or spiral spring bar has been used for the same office. 
Teeth do not loosen so badly in double as in single 
bar cylinders, as the extra length of shank holds 
them from sidewise movement when an excessive 
amount of straw is encountered. A spring steel 
split washer is sometimes used under the nut to keep 
it fast. 

It is needless to add that worn teeth retard the 
proper work of a separator and should be replaced by 
new ones. 

THE CONCAVE. 




The concave, so called because of its dished or 
hollow shape, consists of a rack or grate constructed 
to conform to the cylinder under which it is adjust- 
ably hung. It is provided with teeth which interact 
with the cylinder teeth. It is adjustable to and from 
the cylinder. The concave holds the concave teeth 
in position between the cylinder teeth and forms a 
floor or grate over which the straw passes while 
being acted upon by the cylinder. The open space 
between the teeth permits the shelled grain to fall 
through as soon as dislodged from the heads, thus 



20 SCIENCE OF THRESHING. 

relieving the separating devices from some of the 
work of removing the grain from the straw. Con- 
cave teeth serve the further purpose of retarding the 
grain while it is being acted upon by the cylinder 
teeth. The greater the number of teeth the more the 
straw will be retarded and acted upon by the cylinder. 
Separators are usually constructed to use concaves of 
several sections, each section being provided with two 
or three rows of teeth. In adjusting the position of 
the concave relative to the cylinder, it must be borne 
in mind that some grain requires very positive action 
on the part of the cylinder teeth to dislodge the grain 
from the head; accordingly, when threshing grain 
of that sort it is well to set the concave close and 
employ all the sections. In grain that is less stub- 
born, a section of the concave may be removed and 
replaced by one without teeth with good results. 

There should be stops provided to prevent the 
concave from being raised too high so as to give a 
proper clearance. It is better practice to set the 
concave up close and use few teeth rather than to 
lower the concave and employ a greater number. 
The latter plan leaves a space below the points of the 
cylinder teeth which permits the straw and whole 
heads to pass without being acted upon. If the 
straw be very dry and brittle and inclined to break up 
badly, it lies more loosely and can therefore be given 
a considerable more space by letting the concave 
down. 

Some types of concaves are adjustable, both at 



SCIENCE OF THRESHING. 21 

their front and their rear edges. The proper posi- 
tioning of these has given rise to much discussion, as 
some experts claim that a cylinder is less liable to 
slug when the front edge of the concave is the 
higher, than when the concave is fixed in the opposite 
position, as the wedge shaped opening through which 
the straw passes broadens as the straw progresses and 
does not tend to clog or bunch it. 

THE GRATE. 



A grate formed of slightly separated parallel bars 
through which the kernels may easily fall is placed 
just back of the cylinder. It should be so adjusted 
that the straw in passing from the concave will 
strike it at an angle ; this will aid the separation by 
affording a comparatively straight or unobstructed 
path for the flying kernels which are thereby less 
impeded and fall through more readily. This 
position also allows the passing straw to sweep the 
grate cleanly, and to prevent it loading up with chaff 
and sticks. 



22 SCIENCE OF THRESHING. 

THE FEED BOARD. 

The feed board is a platform placed in front of the 
concave and connects with it, as in hand feeding 
machines on which the sheaves may be cut and spread 
for presenting to the cylinder. The surface of the 
feed board and its extensions, or tables, should be 
smooth, and free from nails or other obstructions, to 
facilitate the moving of the straw. 

If the cylinder does not have sufficient draft or 
pull to take the straw readily enough, the edge of the 
feed board which comes in contact with the concave 
may be rounded or curved; this is usually a good 
remedy. A desirable point in the working of a sepa- 
rator is also gained in that the straw, which passes 
more freely over this rounded edge than it would 
over an abrupt or angular margin, is not broken or 
cut up to any great extent. 

It is good practice to keep the lower edge of the 
feed board on top of the concave close to the cylinder 
teeth, even when the concave is lowered, thus every 
head is acted upon by the cylinder teeth as it passes 
over the concave. 



CHAPTER III. 

THE SEPARATING MEMBERS 

After the unthreshed grain is passed from the 
feed board between the threshing members, the cylin- 
der and concave, and has been beaten and jarred by 
their interacting teeth, the mingled straw and loose 
kernels of grain are delivered to the separating 
members. 




BEATER. 

In its most common form, the beater consists of a 
shaft carrying two circular spiders or heads between 
which are secured beater boards or wings which 
extend edgewise from the center shaft. The office of 
the beater is to move the straw away from the cylin- 
der back to the separating parts. Its chief usefulness 
is in preventing the straw from piling up back of the 
cylinder where it is liable to be caught and wound in 
between the cylinder and concave. This action of 
the machine is called u back lashing." It should be 
so placed as to allow the grain and straw to strike it 
as they come from the cylinder and pass either over 

2 3 



24 SCIENCE OF THRESHING. 

or under it. It serves as a check to the flying kernels 
from the cylinder. However, it is not of much 
benefit as a separating device as its rapid motion 
tends to carry the grain along and throw a portion of 
it on top of the moving straw. Consequently, it 
should be run just fast enough to prevent its catching 
or winding damp or soft straw, its position being 
chosen at the proper distance from the cylinder. 

Other devices are used instead of the beater to pass 
the straw back from the cylinder. One form 
resembling somewhat the cylinder, comprises a drum 
set with teeth. Some machines work very well 
without a beater, the cylinder delivering the straw 
directly to the separating device. 

THE CHECK BOARD. 

The check board is hung directly behind the beater 
to arrest flying kernels. It is a sheet iron apron 
hinged by its upper edge to the separator frame, 
while its lower edge trails on the top of the stream of 
moving straw. It should be so adjusted as to prevent 
any grain passing it and lodging in that part of the 
straw as it is going through the separator. It also 
acts as a compressor o'n the straw, tending to reduce 
it from the loose, fluffy condition in which it leaves 
the beater to a more compact layer. 

The check board has an important part in the 
proper action of the separating devices, and its 
proper adjustment should be carefully studied. 

THE SEPARATING DEVICES 
The part of the machine which is of equal import- 



SCIENCE OF THRESHING. 25 

ance with the threshing members is the mechan- 
ism which separates (hence the name "Separator") 
the shelled grain from the straw in which it is 
entangled. While the operation seems simple 
enough on first thought, there are some things 
involved which render the devising of a successful 
separator very difficult, and as yet no one has con- 
structed a machine which will remove every kernel 
from the loose straw under all conditions of threshing. 
Gravitation is the form of attraction which causes 
unsupported bodies to fall. Owing to inertia, a 
falling body starts to fall quite slowly, its motion 
downward increasing in a fixed ratio as it continues 
to fall. A body placed in a vacuum will fall 16 ft. 
the first second, the first half of the second it falls 
only four ft. while the last half of the second, owing 
to its increased speed, it falls 1 2 ft. It requires one- 
fourth of a second to fall the first foot. The sepa- 
rating of the grain from the straw is done by gravity; 
time must be given the kernels to fall out of the 
straw. In falling they must pass down through the 
small interstices between the stalks. 

If we pick up a quantity of straw between whose 
stalks and leaves loose kernels of grain are entangled, 
we may toss the bunch or bundle around up and down 
a good deal without dislodging the grain. The 
kernels will remain in the straw. We must move the 
stalks of the bundles about among themselves in 
order to shake the kernels out from their resting 
places, and the more mildly and gently we do this, 



26 SCIENCE OF THRESHING. 

within certain limits, the better will be the results. 

All the separating devices in use are for this 
purpose of thoroughly agitating the straw and 
thereby allowing the kernels to fall. This causes a 
limit to the quantity of straw which any machine can 
handle, as time must be given for the dislodging and 
falling of the grain. If the layer of straw travels 
too fast, the grain is carried along with it. If it 
moves too slowly, the size of the column will be 
correspondingly increased. If the straw be damp and 
pliable, it will form a more compact mass than if dry 
and elastic. Some kinds of grain have more leaves 
than other kinds and these mat down closely. 
Separation is retarded by these conditions, and the 
feed should be varied in speed to suit them, so that 
the straw will have a chance to open up and allow the 
grain to work down through the interstices and fall 
out of the layer onto the grain rack before the straw 
reaches the rear of the machine. The intelligent 
thresher will bear these matters in mind and not 
crowd his machine beyond its proper capacity, as the 
result will be unsatisfactory. 

However, any of the separating devices in use will 
handle very large quantities of grain and straw when 
operated intelligently, and the aim should be to gain 
the best results in both quantity and quality of work 
done. 

Having thus noted the requirements to be met in 
adjusting and managing the separating mechanism, 
the different types can be intelligently explained. 



SCIENCE OF THRESHING. 



27 



The separating devices in use may be divided into 
three general classes : first, the kinds wherein the 
straw is given an intermittent or step by step move- 
ment through the machine by means of a vibrating or 
oscillating rack or table; second, kinds where the 
straw is given a continuous onward movement by 
traveling raddles; third, where the straw encounters 
a combination of these two mechanisms. 

There are also accessories such as revolving pickers, 
racks, beaters and fingers which will be duly consid- 
ered. 

THE RACK. 

The rack or table usually consists of a series of 
grates or parallel slats arranged to carry the straw, 
while allowing the grain to fall through. 




In some forms of racks a series of risers are placed 
on the surface, which have lifting fingers which are 
operated by a lever and shaft; they tilt backwords 
along the rack and are given an up and down motion 
as the rack vibrates, lifting and tossing the straw as 
it passes over them. 



2 8 SCIENCE OF THRESHING. 

Motion is imparted to the racks by means of a 
crank. In some instances the rack is hung to links 
so that the crank gives it a swinging motion like a 
pendulum, as is shown in the adjacent cut, its path 
being concave, or the rack may be supported on the 
upper ends of rockers in which case it oscillates back 
and forth in an upwardly curved or convex path. 

The rack has a tendency to jar and compress the 
straw on each upward stroke, tossing it into the air 
very slightly and moving back from under it. The 
elasticity of the straw causes the mass to expand 
while clear of the rack. As it falls, it meets the now 
ascending rack and is thus given another sharp com- 
pressing blow which tends to move the different 
straws in the mass upon each other. The most 
effective blow is given by the rack at the middle of 
the stroke, as the peculiarities of the crank motion 
cause it to travel fastest at about this point. 

It is plain that if a quantity of straw and grain 
should lie on the rack and vibrate up and down with 
the rack, and not move away from it, the stalks 
would maintain their relative positions and not give 
the kernels a chance to fall out. To be effectively 
cleaned, each stalk must be moved as related to its 
neighbor. This inter-motion of the stalks constitutes 
the chief feature of effective separation. 

The motion of the rack should be such that its 
upward stroke will move the straw onward, slightly, 
while the rack is permitted to descend from under it. 
Gravity will then start the straw downward with 
increasing speed as it approaches the rack. The 



SCIENCE OF THRESHING. 29 

motion thus attained will cause it to strike the rack 
with a sharp jarring motion at the midway point 
before mentioned ; if the rack swing has been properly 
timed the weight of the falling straw will add to the 
shock, while the stiffness of each straw will cause it 
to move relatively to its neighbor; as soon as released 
at the up end of the stroke, the mass will expand to its 
normal condition. This jarring, compressing and 
expanding motion accomplishes the desired result in a 
remarkably perfect manner when the layer of straw is 
not too thick or bulky. If it is so deep that the 
jarring motion is not felt in its upper part the result 
is not so good. The upper part will float along 
undisturbed because of the elasticity of the inter- 
vening straw; if the rack is vibrated so as to throw 
the straw quite high, it is liable to toss the grain too 
far and the latter, being heavier, will go higher than 
the straw because of its greater momentum, and 
retard the separation. 

Thus the straw should be made to pass over the 
rack in a layer of even thickness of just the depth to 
be thoroughly and quietly agitated from top to 
bottom, and the motion of the rack should be such as 
to strike it upward blows at the most effective point; 
that is, midway of the upward stroke. 

The stroke of the rack is usually from five to nine 
inches in length and the number per minute varies 
inversely as the length, the long, slow stroke passing 
as much straw along as the short stroke of higher 
rate. 



30 SCIENCE OF THRESHING. 

The manner of separation is seen to be the moving 
of the stalks among themselves to free the confined 
kernels and allowing gravity to act on them, causing 
them to fall out. The speed and motion that moves 
the stalks among themselves with the least upward 
motion is the best for effective separation. 

RADDLES. 

The ordinary raddle is constructed of parallel belts 
running over pulleys, connected by slats which are 
situated far enough apart to permit the grain to fall 
through while carrying the straw along. If their 
motion is quite rapid they work very well, as the 
movement keeps the sheet of traveling straw compar- 
atively thin, thus giving the kernels opportunity to 
fall through. The raddles should be of sufficient 
length to allow all of the grain to work out before 
the straw is passed over. 

Some raddles are agitated by being driven over 
irregularly shaped pulleys which produces a rapid 
jarring motion. This has the effect of moving the 
straws slightly among themselves. 

The point where the straw falls on the raddle 
needs special attention. The straw should be deliv- 
ered to the raddle in a thin, loose mass, for when 
large or close bunches are allowed to drop on it, it 
carries them along without giving them a chance to 
separate or spread out, and thus prevents the kernels 
from falling through. 

As the straw falls on the slats of the raddle, the 
rapidly moving bars give the straw sudden jar or 



SCIENCE OF THRESHING. 3 1 

jerk and have a tendency to tear the mass or layer of 
straw apart. The greater part of the separation is 
done at this point where the straw falls on the raddle. 
The operation seems to be more effective if the straw 
is permitted to fall a little distance before it strikes 
the raddle. The impetus of the falling straw added 
to the force of the blow given while the direction 
which the straw takes is changed, also aids in the 
separation; if the straw is moving in the same direc- 
tion as the raddle when it comes in contact with it, 
the jarring and pulling apart motion is eliminated, 
and the straw passes along quietly without change 
of direction or change of position of the stalks in 
reference to each other, so that the kernels are not 
disentangled. 

THE COMBINATION OF RACK AND RADDLE. 

In the combination of the vibrating rack with the 
traveling raddle, the straw usually passes over the 
rack first and is then delivered to the raddle; the 
straw is pulled apart and thinned by the rapid motion 
of the raddle, which disposes of the straw very 
quickly and usually faster than it is delivered. This 
pulling apart process greatly aids separation at this 
point. 



CHAPTER IV. 

GRAIN CLEANING MEMBERS 

In separating the grain from the straw, a large 
quantity of chaff and refuse passes out with the ker- 
nels. This is disposed of by passing the uncleaned 
grain over a series of sieves, through which a current 
or blast of air is forced. The combination of sieves 
and blast fan is called the cleaning mill or shoe, and 
takes the place of the fanning blanket of the old 
threshing floor or the fanning mill of recent years. 

There are three things to be considered in refer- 
ence to the cleaning mill or shoe, on which its 
successful working depends, namely, the sieves, the 
blast, and the sieve motion. The sieves should be 
adapted to the kind of grain to be threshed and as 
few as will do the work should be used, a greater 
number retarding the blast and catching straw and 
sticks. The blast should be strong enough to flow 
constantly through the sieves, even when the latter 
are heavily loaded. The motion of the sieves should 
be sufficient to insure movement of the chaff and 
kernels on the sieve surface. 

THE SIEVES. 
The sieve comprises a frame, mainly of wood, and 
a woven wire or sheet metal body. The best prac- 
tice of to-day favors perforated or corrugated sheet 
metal sieves, although the wire mesh is still used. 

32 



SCIENCE OF THRESHING. 33 

A properly constructed sieve permits the grain to 
fall through it, passing the chaff and refuse over it, 
without allowing the straw and sticks to be retained 
in the meshes, and directs the blast in the proper 
direction. In practice, a sieve adapted to each kind 
of work is used, though some combinations of sieves 
work very well on several different grains. The 
usual plan is to permanently secure the upper sieve, 
called the chaffer, it being of sufficiently large mesh 
to adapt it to the coarsest grains. The lower sieve 
or sieves are interchangeably secured so that they can 
be varied according to the work to be done. 

Adjustable sieves are constructed to change the 
size of the opening of the meshes to suit different 
kinds of grain, the usual construction being a frame in 
which are hinged cross slats. The adjusting of the 
slats changes the opening, also changes the angle 
of the blast through the sieve. When the slats are 
tipped back the openings are reduced in size, and the 
blast directed in a more backward direction. 

The openings in the sieve must be large enough to 
permit the free passage of the clean kernels, and 
should be sufficient in number not to retard the blast. 
If the openings are too small or too few in number, 
the grain accumulates on the sieve and passes over 
into the tailings elevator, by which it is carried back 
to the cylinder. This greatly reduces the capacity of 
the machine as it needlessly increases the amount of 
grain it is required to separate. If the openings, on 
the other hand are too large, they permit the sticks 



34 SCIENCE OF THRESHING. 

and straw to pass out with the grain, causing it to be 
dirty and poorly cleaned. 

The openings should be so shaped as to direct the 
flow of the blast in the proper direction, which is 
approximately at right angles to the sieve surface. 
This prevents the blast from blowing the grain along 
the sieve surface. If there are too many openings, 
— and this is the case in a wire sieve — too much of a 
blast passes through; this causes so strong a current 
above the sieve that it prevents kernels which are 
lifted from the surface, from falling again umil the 
rear of the sieve is reached. 

The sieves should be stiff and rigid so as not to 
spring at the center; otherwise the motion will be too 
violent there and throw the grain so high as to keep 
it from falling through the sieve. A sieve frame 
which travels two inches at each stroke and makes 
two hundred and fifty strokes a minute, goes five hun- 
dred inches every minute ; if its center springs an inch, 
it goes three inches at every stroke, or seven hundred 
and fifty feet a minute, a motion which may be alto- 
gether too violent for that part of the grain which 
falls on the center of the sieve. 

THE FAN. 

A fan is a device for producing a blast or current 
of air. The usual form used in separators consists of 
a central shaft from which radiate arms which carry 
blades or wings. These revolve in a casing, and the 
rapid motion of the outer ends of the blades forces 
the air to rush out of an opening in the side of the 



SCIENCE OF THRESHING. 35 

casing. 

This air is replaced by a current which enters a 
central opening at the ends of the casing. 

Fans are overblast when the upper blades travel 
towards the outlet; they are called underblast when 
the lower blades move toward the mouth. 

THE BLAST. 

The blast is an important feature of the cleaning 
mill. It should lift the chaff and light matter and 
prevent it from falling through the sieve openings, 
and at the same time maintain a continuous flow 
through the sieve. It should be strongest in the 
sieve openings, and light above the sieve surface. 
When these conditions are secured, if the blast lift a 
kernel, it will ascend but a short distance before it 
again returns to the sieve; if the blast were as strong 
above the sieve as at the meshes, the kernel would 
be blown out with the blast and wasted. 

To obtain these conditions, the solid or blind 
portions of the sieve should be in proper proportion 
to the openings; practice establishes this at about 
five to seven. That is to say, the solid portion of the 
sieve should be about five-twelfths of the surface, and 
the openings should be, in, the aggregate, about seven- 
twelfths of the surface. It will be observed in using 
a sieve of these proportions, that the blast will be 
only seven-twelfths as strong just above the surface 
as in the meshes. It is to be noted that this state- 
ment is more strictly correct when the direction of the 
blast is at about right angles to the sieve. 



36 SCIENCE OF THRESHING. 

The blast should be sufficiently strong to insure its 
continual flow under all circumstances and conditions, 
but not fast enough to blow any of the grain over 
with the chaff. 

There is a difference between a blast of strong 
pressure and a blast of high speed. A current of air 
may be traveling slowly, and still go with force and 
be difficult to stop, as is that produced from a slow 
moving air-pump; or it may be moving quite rapidly 
but with no particular force more than the momentum 
produced by its own weight, like the zephyr of a 
summer day or the breeze from a lady's fan. The 
least obstruction would stop or turn such a blast. 

THE KERNELS OF GRAIN WILL FALL THROUGH A 
BLAST OF ANY PRESSURE OR STRENGTH, BUT WILL 
NOT FALL THROUGH A VERY RAPIDLY TRAVELING 
BLAST. 

The chaff is easily lifted on account of its light 
weight. To do good work then, it requires a mild 
or slow blast delivered with strength or force. This 
blast should be spread under the entire surface of the 
sieve and be made to flow through every mesh. It 
should be strongest and of greatest quantity at the 
front end of the sieve, which receives the grain and 
chaff, for it is here that the greatest work is to be 
done in lifting the sheet of chaff intermingled with 
grain. It should decrease in quantity and pressure 
toward the rear end where the least work is required. 
Thus if a light kernel has been lifted with the chaff 
at the front end, it will have a chance to fall before 
reaching the rear end of the sieve. If the blast is 



SCIENCE OF THRESHING. 37 

made to pass through the chaff, as soon as it enters 
the upper sieve it will lift and scatter it, the lightest 
flying out first, thus giving the kernel an opportunity 
to fall through the sieve much more quickly and 
freely than if the blast were not strong enough to 
keep the meshes open and clear of chaff. Besides, if 
the blast ceases to flow through any of the meshes, 
the fine dust and chaff will fall through and cause the 
second sieve to be overloaded, and thus the grain may 
retain a part of the chaff and dirt. 

SIEVE MOTION. 

The motion of the shoe should be sufficiently 
strong and rapid to move the grain and chaff on the 
surface of the sieves. Too strong a motion will 
interfere with the kernels falling through the meshes 
properly, and cause the grain to be carried over, either 
with the chaff or into the tailings spout. It is found in 
practice that the upper sieve or chaffer requires a 
more violent and positive motion than the lower 
sieves, on account of the great quantities of chaff 
and cut straw to be carried. For this reason the 
chaffer is usually placed in a different frame and 
given a longer stroke while the remaining sieves have 
a short and rapid motion. 

The coarser and looser the material to be handled, 
the longer and more vigorous the motion should be. 
The straw rack which is loaded with loose, fluffy 
straw, requires quite a long stroke to be effective, 
while the conveyor and chaffer sieves need less 
motion and the shoe sieves still less. 



38 SCIENCE OF THRESHING. 

It will be seen that if the straw rack had a slight 
motion, it would not handle or scarcely move the 
straw at all, while if the conveyor and chaffer sieves 
had as much motion as the straw rack, they would 
throw the grain so fiercely as to prevent a good 
portion of it from passing through. This is because 
of the difference in the elasticity or springiness of the 
materials to be moved. It is thus quite essential that 
the motion should be adapted to the class of work to 
be done. In end shake sieves, that is, where the 
stroke is endwise of the machine, this motion should 
be upwards and backwards with quite an uplift, and 
should be just strong or rapid enough to cause the 
grain to be carried along as quietly as possible. 

In side shake sieves, that is, where the motion is 
sidewise to the machine, the motion should be suffi- 
ciently strong and long to cause the sieve to move 
continually under the grain and chaff, thereby aiding 
the blast in carrying the chaff along toward the rear. 

The blast may be at a greater angle from the 
perpendicular in side shake sieves than in end shake 
sieves as it is the only means of carrying the chaff and 
refuse along to the rear. 

In the end shake sieve, the upward and backward 
motion assists in moving the mass. 

Side shake sieves may be given an upward 
rocking at each side, as the stroke is finished. 
This is accomplished by using comparatively short 
hangers and adjusting them at an angle (sidewise to 
the machine). As the sieve is moved sideways, one 
side will continue to rise, and the other to lower 



SCIENCE OF THRESHING. 39 

somewhat, causing it to give the grain a slight 
upward motion at each stroke. This motion varies 
in different places on the surface of the sieve, beino- 
nearly parallel thereto at the center. 

The blast and sieve motion should be properly 
gauged one by the other, and by the working condi- 
tions. It is necessary for a shoe using a weak blast 
to be given a greater motion to assist in carrying off 
the refuse and chaff, when the blast is overtaxed, as 
when an undue amount of chaff and cut straw loaded 
with dust isdelivered to it, or in damp threshing. 



CHAPTER V. 
THE DELIVERY MEMBERS 

WIND STACKERS 

The use of an air blast for stacking the straw has 
become common. The air, straw and chaff are blown 
from the interior of the machine by a suitable fan 
through a pipe, the object being to direct the blast 
so that a stack may be easily formed. 

When the pneumatic stacker was first introduced 
the item of power was an important one. The first 
fans used had large wings running at a high rate of 
speed, and it is safe to say that it required as much 
power to operate the stacker as it did to run the 
rest of the separator. At first the fans were belted 
to run from 1,000 to 1,700 revolutions per minute; 
the enormous power required to do this either stalled 
the engine or slipped the belt so that in fact the fans 
were driven at much slower speed. 

In present practice the fan is driven at from 300 to 
500 revolutions per minute and the blades of the fans 
have been reduced, so that the power required is 
greatly lessened. The work performed by the fan 
of the wind stacker is setting the air and straw in 
motion and forcing it through the straw pipe. The 
more air set in motion and the greater speed given it, 
the more power required. The weight of air passing 

40 



SCIENCE OE THRESHING. 41 

through the straw pipe exceeds that of the straw, 
that is, there are more pounds of air than pounds of 
straw set in motion hy the fan. So, in determining 
the work performed by the fan, the item of air can 
be figured, as the more straw there is, the less air 
there is, and consequently the less weight. The 
actual foot pounds or horse power expended is 
determined as follows : Multiply the area of the 
straw pipe by the number of feet the air travels per 
minute; multiply this by the pressure required to 
produce this speed; the result, which gives the 
number of foot pounds, divided by 33,000 is the 
horse power. Thus, the area of the usual 15 in. 
stacker pipe is 176 sq. in. A pressure of one ounce 
per sq. in. gives a velocity of 5. 161 feet per second to 
the air. 176X5.161=908,336 ounces, which, di- 
vided by 16, the number of ounces in a pound, equals 
56,271 foot pounds. Dividing this by 33,000, the 
number of foot pounds in a horse power, equals i ^4 
horse power approximately. At this velocity and 
pressure about 14 tons of air and straw per hour 
pass through a 15 inch pipe (of which about ten 
tons of air and four tons of straw represent a fair 
average.) There is of course more dry straw blown 
through in a given time than wet straw. 

Some power is lost by leakage around the fan and 
at its center; also cutting and chopping the straw. 
A slow moving fan moving a large amount of air 
steadily is better than a fast turning one, as the 
increased friction of the more rapid current absorbs 
a great deal of energy. Some experiments along this 



42 SCIENCE OF THRESHING. 

line strikingly show this increase. A good type of 
fan was run at its normal slow speed of approx- 
imately 400 revolutions per minute and furnished the 
normal pressure. The speed was then gradually 
increased one-quarter, or to practically 500 revolu- 
tions per minute. It was found that the pressure had 
increased about 16 2/3 %, and the power 35 1/3 %, 
or in round numbers, an increase of one-quarter in 
speed gave an increase of one-sixth in pressure and 
used one-third more power. 

HANDLING THE THRESHED GRAIN. 

There are a variety of weighers, measurers, sackers 
and wagon loaders on the market and in use to 
handle the cleaned grain as it comes from the 
machine. 

Included among these is a class that measures the 
grain as it is threshed and registers the number of 
bushels as delivered; also a class that measures the 
grain instead of weighing it, and keeps a tally or 
record of the amount. There is also a short sacker, 
requiring a man to operate it, which aids in sacking 
the grain, and a wagon loader which delivers the 
grain to either side of the machine without making 
record of the amount handled. 



CHAPTER VI. 

FEEDING 

Supplying the grain or feeding should be done as 
steadily and uniformly as possible in order to keep a 
continuous stream of grain passing through the 
cylinder. This keeps the engine working with uni- 
form steam and tension on the belt. 

When grain is fed into the cylinder, the speed of 
the latter is checked. As soon as this checking is 
felt on the main drive belt, the engine speed is 
decreased until the governor has time to act and, by 
admitting more steam, restore the normal motion 
to the engine. This change causes the engine to pull 
harder on the belt. If, while this tension is on, the 
cylinder suddenly runs out of straw, the speed at once 
increases in obedience to the extra strain on the belt, 
as it takes a little time to communicate this change of 
speed to the governor and have it cut off the steam. 
The result is a see-sawing motion every time that a 
bundle goes into the machine, unless it is properly 
divided and lapped on the preceding bundle. An 
entire bundle, especially if it is large or compact 
enough to slug, should never be allowed to enter the 
cylinder. 

The average cylinder teeth are about three inches 
long. The concave teeth occupy about one-third of 

43 



44 



SCIENCE OF THRESHING. 



the space between the concave and cylinder bars, thus 
leaving about two inches through which the bundle 
must be passed. This compressing process of the 
teeth consumes a large amount of power. A five 
hundred pound cylinder has a momentum or striking 
force of thirteen hundred and twenty tons. This 
indicates the terrible strain on the machine when a 
bundle is fed in of sufficient size to stop the cylinder, 
although this does not often happen. But the power 
consumed when the bundles are not properly divided 
up is enormous, and is still further increased when 
the straw is damp and tough, as tough and pliable 
straw clings more firmly to the cylinder teeth than 
does dry and brittle straw. 




SELF-FEEDERS. 



Self-feeders are of comparatively recent develop- 
ment, though they have been experimented with for 
several years. After patient study and many unsuc- 
cessful trials, the feeder and band cutter has reached 



SCIENCE OF THRESHING. 45 

a degree of perfection that makes it a desirable part 
of the complete threshing rig. 

The office of the self-feeder is to cut the bands, 
loosen the bundle, dividing it in a sufficiently thin 
body, and present it to the cylinder in a manner that 
will not permit slugging or choking of the cylinder. 
To do this successfully it is necessary that the bundles 
should be drawn out or elongated endwise, or divided 
in some way that the cylinder may not receive the 
whole bundle at one time. The usual method of 
accomplishing this is to pass the lower part of the 
bundle towards the cylinder slowly while the top part 
has its speed increased by some faster traveling mech- 
anism above it, forcing the top straws ahead while the 
lower ones are being retarded and this must be accom- 
plished before the bundle reaches the cylinder. The 
more thoroughly this is done the better the feeder and 
the machine seem to work. 

There has been some experimenting with governors 
to regulate the amount being fed to the machine and 
they are being used with more or less success. Some 
depend on the speed of the cylinder to disengage a 
mechanism whereby the feeder is thrown out of gear 
when the speed is reduced below a predetermined 
number of revolutions per minute. Others regulate 
by the amount or bulk of the traveling column of 
straw. 

The bundles in most feeders are first deposited on 
the carrier, on which they are carried along to the 
band cutting device by means of a raddle constructed 
of belting with laterally secured slats, or a canvas cov- 



46 SCIENCE OF THRESHING. 

ered table. As the bundles move towards the 
cylinder, they are acted upon by the band cutters, 
which should be sufficiently near together and travel 
close enough to the table, to insure all the bands 
being cut. It is also necessary that the bundles 
should be thoroughly picked apart and loosened up 
before reaching the cylinder. The band cutters in 
most of the feeders perform this office also, by 
passing the knives rapidly into the bundle among the 
straws in such a manner as to throw the top straws 
ahead toward the cylinder. 

A separator with a properly constructed self- 
feeder will require but very little more power to 
thresh a given amount of grain in a given time, as 
it divides up the bundles and feeds clear across the 
cylinder much better than is done by hand. But with 
the use of self-feeders the pitchers usually pass 
the bundles along a little faster because they do not 
have to use the same caution about placing them on 
the table as they do in hand feeding. The only thing 
they need to observe is the amount or quantity being 
handled. 



CHAPTER VII. 

OPERATION 

In operation the separator, like any other machine, 
does its work best when properly adjusted and 
managed. There is no machine which has a more 
varied scope of work or which has to encounter so 
many conditions. It is rare that there are two fields 
of grain grown, ripened, cut and handled under like 
conditions; one may be in a condition to shell from 
the straw readily, while in another the kernels may 
cling to the head so as to make it almost impossible 
to dislodge them. One stack may be brittle and break 
too readily, while the next may pass through without 
this annoyance. One kind may be stiff and stubborn 
and another soft and pliable; one lot may have many 
blades or leaves on the stalks, another only the plain 
stalks and heads; one kind may have a light, fluffy 
chaff and heavy kernels, and another the reverse, 
heavy chaff filled with sap and light kernels. 
Some fields are filled with weeds and foreign matter 
which the machine is expected to distinguish and 
separate from the grain. 

Then again, there are conditions of the weather 
which appreciably influence the working of the 
machine, and cause a wide variation in the amount 
of power required. Some days are bright and sun- 
shiny, others damp and foggy. Some are warm or 

47 



48 SCIENCE OF THRESHING. 

hot, others cold. There may be a hard wind blowing 
or there may be none. All these various conditions 
affect the machine, each in a peculiar way. The 
operator is expected to save every kernel, perfectly 
cleaned, and do many other things equally well nigh 
impossible, notwithstanding these varied conditions. 
The man who best understands the machine and its 
workings will come the nearest to perfection in 
managing it. 

As before stated, the cylinder is a vital part and 
should receive special attention and be kept in good 
condition. If it is out of balance appreciably, it 
should be taken from the machine and set on the 
straight edges, as explained before, and restored to 
balance by inserting counterbalancing weights in the 
light side. The boxes should not run too tight, as 
the extra friction consumes a large amount of power. 

The teeth should not be allowed to become so 
worn and rounded as not to draw the straw into the 
machine freely. By replacing the worn by new teeth, 
evenly distributed around the cylinder, the straw will 
be readily pulled in and the grain threshed clean. 
Care should be taken to keep the teeth properly 
spaced; any bent ones may be trued up with the 
tooth straightener, or by the use of a heavy hammer. 

The cracking of grain is usually caused by one or 
more cylinder teeth running so close to the concave 
bottom, or teeth, as not to permit a whole kernel of 
grain to pass; the resultant wedging cracks or breaks 
the grain. Another cause is the repeated passing of 



SCIENCE OF THRESHING. 49 

the grain through the cylinder by the tailings elevator. 
Each time a kernel receives a blow from a cylinder 
tooth it is partially disintegrated, and many blows 
crack or break it open. 

Only enough concave teeth should be used to 
retard the passage of the straw through the concave 
a sufficient length of time to allow all the kernels to 
be loosened. More teeth than are required to do 
this consume power unnecessarily as well as cut up 
the straw to such an extent as to interfere with the 
proper workings of the separating and cleaning 
mechanisms. The machine will often do better 
work with two or four rows of teeth than with 
more. In handling oats, two rows of teeth are com- 
monly enough, except when the kernel is small and 
light and the oats, which may have been cut when 
green, seem tough and cling to the heads; in this 
case high speed in the cylinder and more rows of 
teeth in the concave are required to loosen all of the 
kernels from the straw. 

For use in sections of the country where flax is 
grown the concave should be specially designed with 
teeth set near together, as some conditions require 
very close adjustment to enable them to break open 
the balls containing the seeds. Under some condi- 
tions, the ball is often found to be saturated with an 
oily, gummy substance which makes it very tough; 
it is then liable to break off from the stalks and pass 
whole through the machine. To meet such condi- 
tions, use all the concave teeth possible and run the 
cylinder at a high rate of speed, arranging the parts 



50 SCIENCE OF THRESHING. 

at the rear of the machine to return the unbroken 
halls through the tailings elevator. 

In threshing barley, plenty of concave teeth and a 
high cylinder speed break off or "nub" the beard 
effectually. 

The grate, as before indicated, which lies back of 
the cylinder, should have its rear edge raised so that 
the straw and grain, as it comes from the cylinder, 
should strike its face at a slight angle. This keeps it 
clean and prevents it from loading up with thick or 
brittle straw. 

The beater should be in a position for the straw 
and grain, as it comes from the cylinder, to pass it 
without changing its course too much; that is, it 
should be so adjusted that the straw will not strike it 
near its center, as the straw would then have to 
change its course to pass around it. 

If the beater is arranged to allow the straw to pass 
under it, the wings of the beater or beater boards 
should have just sufficient contact w T ith the straw to 
keep it moving. 

In the scheme of separation, the first essential 
feature is to have the threshing members deliver the 
straw to the separating devices with the kernels all 
threshed from the heads and the straw unbroken. 
Whole straw will not pack as closely and hold the 
kernels in consequence as does broken or cut straw. 
Stalks that are heavily loaded with leaves form a com- 
pact, homogeneous mass which retains the kernels, 
and are consequently hard to separate. 

Oats are frequently hard to separate. - In some 



SCIENCE OF THRESHING. 5 1 

sections of the country rust is prevalent; this forms 
on the stalks and leaves before they are harvested, 
making them brittle, while it blights the kernels, 
which are, in consequence, light. The rust on the 
stalks has a certain clinging roughness that causes 
them to adhere to each other and therefore retards 
the disintegrating effect of the rack or raddle which 
does not move them among themselves but allows 
them to travel along in a compact mass. In such 
case, all that can be done is to adjust the machine to 
the best advantage, run at good speed and regulate 
carefully the amount fed to the other conditions. 

Rye is usually very easily separated, as the stalks 
are stiff, and comparatively little chaff and dirt is 
found. In some instances the straw is so loose and 
fluffy as to prevent it being worked back fast enough 
by the separating devices, thereby causing the body 
of the machine to choke up. In case this happens, cut 
the straw up by inserting more teeth in the concave. 
By weighting down the check board of a vibrating 
or rack machine it will compress the straw somewhat 
and give the table a better chance to handle it. A 
convenient way of doing this is by fastening a piece 
of wood or iron lengthwise along its back by suitable 
screws or bolts. 

As stated before, it is quite essential that the 
machine stand quite still on its truck while in opera- 
tion. There is a great difference between the opera- 
tion of the machine when the frame work is standing 
still and the mechanisms have their full motion, and 



52 SCIENCE OF THRESHING. 

its working when the frame does a part of the 
moving, which the mechanisms complete. 

There is another reason why the separator should 
be made to stand still. When the engine is running, 
one part of the drive belt is drawn tight while the 
other is slack. The harder the engine is being driven, 
the tighter will the belt be drawn; if the separator 
is rocking on its trucks to and from the engine it will 
take up some of the slack of the belt as it sways 
toward the engine and when moving backward away 
from the engine the belt will either have to stretch 
or slip upon the pulley, as it cannot change the speed 
of the cylinder. As the slack has already been taken 
up it is very likely to slip, an action which is very 
hard on the pulley lagging, and on the belt, and 
which wastes a great deal of power. This slipping 
and straining of the belt is greatly augmented if the 
engine also moves upon its trucks, as the vibrations 
of the two machines will not be the same, and when 
one is rocking in one direction, and the other in the 
opposite direction, there will be double the pull on 
the belt. If a horse power is used, there is the same 
need for the separator to stand still, as the strain 
from the oscillations and vibrations are very severe 
on the tumbling rods. 

If the separator fails to take the grain out of the 
straw properly, it is usually because of one or more 
of the following reasons, viz. : 

The separator is not standing still on its trucks; 
it is not running at the proper speed; the cylinder 
fails to thresh all the kernels out of the heads; the 



SCIENCE OF THRESHING. 53 

separating device or shoe is not level; or the machine 
is being crowded beyond its capacity. 

The shoe or cleaning mill should receive special 
study by anyone who intends to make threshing a 
success. Though the device appears very simple, it 
has many features, as already stated, which are not 
generally understood. 

The motion of the shoe varies in different 
machines. In some it is as short as five-eighths of an 
inch, in others it is four inches; though there is not 
so much speed variance in the motion of the upper 
sieve or chaffer, which generally is from three to four 
inches. The following rule is as close to a correct 
expression of the true principle of its working as can 
be stated: 

"The shorter the stroke, the more vibrations per 
minute are required; the longer the stroke, the fewer 
vibrations per minute are required." 

The speed should be just strong and quick enough 
to throw the straw but slightly at the upper finish of 
the stroke; if it does more than this, it will carry or 
throw the grain, as well as the dirt, and a part of it 
will pass out with the chaff. If the motion is not 
strong enough to cause the grain to leave the upper 
surface of the sieve slightly at each stroke, the 
meshes become filled with grain and chaff, and the 
sieve or chaffer becomes choked to such an extent as 
to allow but little to pass through. If the mechan- 
ism is such that the upper part of the stroke is strong 
and quick, while the lower part is slow and gentle, it 



54 SCIENCE OF THRESHING. 

is all the better, as the upper part of the movement 
will do the throwing and agitating, while the slow 
part of the stroke will allow the sieve time to come to 
rest for an instant, thereby permitting the kernels to 
fall through. 

The boxes and connections that operate the shoe 
should be kept in good order and not permitted to 
work loose, as the lost motion causes a pounding that 
jars the sieve, which springs and trembles; this 
impedes the passage of the grain. 



CHAPTER VIII 



THE BLAST 

The blast requires its share of attention, and when 
it is once thoroughly understood and mastered, it 
becomes an obedient servant capable of accom- 
plishing good work. But few changes have been 
made in the blast fans since they were first used in 
separators. They have faults as well as virtues; they 
do not always send the proper amount of blast just 
where it is intended they should or where it is needed 
the most. 

There is a great difference in the condition of the 
material which the shoe has to handle at different 
times, each section of the country furnishing a partic- 
ular kind or quality of grain to be threshed. In parts 
of the country where spring wheat is raised, there is 
more work for the shoe to do, as there is more chaff ; 
the straw, as it is stiff and hard to thresh, breaks up 
more than does that of the winter wheat raised in 
other sections of the country. Though the kernels 
of spring wheat are not much heavier than the 
berries of the winter variety, the chaff and dust from 
the former is much more dense and weighty than 
from the latter, requiring more than double the 
pressure of blast to penetrate and lift it. 

The cylinder and concave should be adjusted to 

55 



56 SCIENCE OF THRESHING. 

get the grain out with as little cutting up of the straw 
as possible, thereby relieving the shoe of an undue 
amount of work. 

As the grain and chaff are delivered to the front 
end of the chaffer, the kernels are more or less 
thoroughly intermingled with the refuse, the mixed 
mass being of a depth and quality dependent on the 
amount being threshed. It is plain that if the meshes 
of the chaffer are not large enough to let the whole 
mass through, the most of the kernels will be carried 
along with the chaff and dirt by the action of the 
chaffer to the rear end. But force a little blast 
through and watch the result; as the blast comes 
through the meshes, it lifts grain, straw and all. 
The kernels at the bottom of the mass will fall 
of their own weight through the sieve. As the 
blast continues on its way up through and between 
the different particles of the mass, it loosens and sepa- 
rates it, carrying the lightest bits farthest, and 
allowing the others to fall of their own weight. By 
watching the blast still longer it will be noticed that 
the particles which are traveling through the air are 
entirely free from contact with each other, every 
particle seeming to try to avoid its neighbors as much 
as possible. There are never any bunches clinging 
together, but the mass is thoroughly divided, thus 
producing the very best conditions for separating the 
kernels from the chaff. 

The blast should be strong enough at the front of 
the sieve to always flow through the very first 



SCIENCE OF THRESHING. 57 

meshes with sufficient force to keep them cleared and 
to itself pass up through the layer of chaff and grain 
as it passes along; but it should not blow fast enough 
to lift the light kernels very high. There is a differ- 
ence between strength of blast and speed of blast. 
The blast should have strength, but not much speed. 
A horse might be very strong and able to move a 
heavy load, but not move it very fast. The horse 
would then be able to go at a constant and uniform 
speed whether loaded heavily or lightly. So the 
blast in the shoe should be able to move at its regular, 
constant speed, regardless of the amount of grain to 
be handled. It is plain that it should be the strongest 
at the front end of the chaffer where the load is 
heaviest, the chaff being mixed with the grain and 
packed together at that point. After the blast has 
once penetrated the layer and has lifted the chaff up 
in the air it does not need as strong a blast to keep it 
there. In some wrongly constructed chaffers, the 
reverse conditions are found; the blast being 
strongest at the rear end of the chaffer and weakest 
at the front end. In such cases, the heavier the load 
of chaff which comes in at the front end, the harder 
the blast will be at the rear, for as soon as a little too 
much grain and chaff enter the front end and clog the 
meshes, the blast ceases to escape there and is forced 
along under the sieve to its rear end; here it is 
confined and deflected upward by the bottom of the 
shoe, escaping through the rear meshes with force 
enough to carry kernels and all along with it. 

If a shoe is found in this condition, the remedy is 



58 SCIENCE OF THRESHING. 

to arrange the blast or deflecting boards in such a 
manner as to cause the blast to strike the front end 
more forcibly. 

To aid in this adjustment, it will be well to consider 
first, some of the peculiarities of the fan and its 
action on the air. As it revolves the wings make the 
air revolve along with it. As each wing passes the 
outlet, a small portion of the air is thrown off by 
centrifugal force, other air coming in through the 
inlet to take its place in the center of the fan. 

As the fan revolves there is a slight increase of 
pressure of the air against the front side of the wing, 
and a corresponding decrease along the rear side, the 
sum of these plus and minus pressures being nearly 
equal to the atmospheric pressure. 

As each wing passes the outlet opening in the shoe 
the air starts to rush in behind the wing from the 
shoe to fill the slight or partial vacuum on the rear of 
the wing. A small portion thus enters the fan casing; 
the next wing as it comes round, has a tendency to 
force this intruding portion back before it has entered 
very far. This alternate rarefaction and compressing 
action of the fan causes the low vibrating or humming 
sound heard in fast running fans. Now this action of 
the air is not uniform along the entire length of the 
wing. The most air is forced out at the center of the 
shoe, which materially affects the action of the blast 
through the sieves. 

When a fan whose casing is open at both ends to 
admit air, is in motion, the two opposite moving col- 



SCIENCE OF THRESHING. 59 

umns of air rushing in from either end meet at about 
the center. This meeting of the opposing blasts 
increases the pressure somewhat at this central point, 
consequently the fan delivers more freely at the center 
of the outlet; further, the air rushes in more freely 
behind the ends of the wing as it passes the outlet as 
the pressure or vacuum is greater there than at the 
center of the wing; therefore, the air passes from the 
sieves into the fan near the ends of the wings, instead 
of from the fan through the sieves. This motion is 
more marked in long than in short fans, therefore in 
wide than narrow machines. 

A further explanation of this usually unrecognized 
phenomenon is this: As the air rushes from the ends 
towards the center of the fan, there is little side pres- 
sure towards the sieves at the ends of the fans and the 
extra pressure in the sieves forces the air back into the 
fan; that is, the air, for a little distance from the fan 
ends, travels in the wrong direction ; as the air comes 
from the center of the fan, it thus swings back upon 
itself, forming an eddy. Should this counter current 
be strong. enough, it results in carrying some of the 
grain along with it into the fan. This effect is so 
marked in some machines that the corners of the fan 
are worn by striking the grain blown in by this 
motion of the blast. This effects the perfect cleaning, 
as the direction of the blast is down at the corners 
of the sieves, thereby carrying the chaff and dirt into 
the grain. 

This whirling motion can be tested in any machine 
by taking the sieves out and running the machine 



60 SCIENCE OF THRESHING. 

empty. When the machine is in motion, take a cane 
or stick of convenient length and fasten one end of a 
ribbon four or five inches long to one extremity. If 
held in the blast near the fan outlet, the ribbon will 
indicate the way the current of air is moving. 

Further study of the blast will show that its direc- 
tion is not in a direct line from the point of delivery 
of the faa along the stationary blast boards at the top 
or bottom, towards the sieves, but tends to follow the 
curve of the fan casing until it comes against the 
blast board. Furthermore, in the case of an under- 
blast fan, the blast does not leave the fan and travel 
in a straight line along the bottom board towards the 
sieves, but extends in a thin sharply defined current 
along near the fan, and increases slightly in thickness 
until it reaches the top blast board, from which it is 
deflected down and back. 

The slight compression of the air at the center, 
makes it veer off at an angle towards each corner, so 
that it blows harder at the rear corners than it does 
at the central portion. 

Two or three narrow wind boards one or two 
inches wide, placed parallel to each other and the fan 
in the forward part of the shoe below the sieves, 
greatly aid in equalizing and adjusting the blast. 
They should be set at an angle which will deflect the 
blast toward the forward part of the sieves and 
should be near enough together to require a little 
pressure to force the blast between them. This 
arrangement makes the air pass out along the entire 
length of the fan opening to relieve the pressure on 



SCIENCE OF THRESHING. 6 1 

the fan side, and will tend to make the blast uniform 
for the entire width of the sieve. 

As before stated there are a great variety of sieves, 
the woven wire ones having the preference in former 
years. They admit the blast very freely and the 
straws run through the meshes and fill them up, so 
they are in some disfavor now. The present ten- 
dency is toward sheet metal sieves having either a 
plain perforated surface or irregular lips and corru- 
gations and lips. Chaffers are frequently made of 
wooden slats set at an angle, or with plain wood, 
perforated at an angle to the surface. 

The angle of the blast as it passes through the 
sie\ T e should be upward rather than backward. The 
reason is that a kernel will fall through a perpendic- 
ular blast better than through an angularly directed 
one, and a perpendicular blast also lifts the chaff 
from the sieve better. 

The correct direction is given the blast by proper 
adjustment of the lip or slat forming the sieve meshes, 
the blast taking its direction from the lip. 

The holes or meshes should be only large enough 
to allow the grain to pass through freely. When the 
sieve is properly constructed and the blast properly 
adjusted, there need be no waste and the grain will be 
well cleaned. When the shoe is working properly, 
there will be a very small quantity of tailings to 
return to the cylinder. (Tailings, so-called, are the 
grain and chaff which did not go through the sieves, 
but are passed over the chaffer.) That this is so will 
be seen if it is remembered that when the blast strikes 



62 SCIENCE OF THRESHING. 

every mesh in the chaffer properly, it will prevent any 
chaff from passing through and will blow it into the 
straw to be carried away with it. Besides, if the 
chaffer is properly constructed and has the right 
motion, as soon as the blast clears the forward 
meshes of chaff, the grain will fall through at once, 
and will then have the entire length of the sieve to 
travel over before reaching the tailings spout, so that 
there will be little chance of its being carried around 
with the tailings. This is the crucial test of a 
properly adjusted shoe, for if the blast does not pass 
through the layer of grain and chaff until it has 
passed half way along the sieve, or more, it is plain 
that a part of the chaff has been sifting through the 
sieve where there is no blast felt. The chaff will then 
find its exit along the next lower sieve to the tailings 
spout. A portion of the grain cannot pass through 
the chaffer at the front end, but is carried along with 
the chaff to the point where the blast first affects' it. 
This may be so near the tailings spout as to cause the 
grain to be carried over into the straw, or to go back 
to the cylinder with the tailings, thus overloading the 
elevator and unduly taxing the capacity of the sepa- 
rating and cleaning devices, and this continued return 
of the kernels to the cylinder is liable to crack or 
crush them. As few sieves as possible should be used. 
Oats usually require only one. In weedy wheat, in 
some instances, a second sieve in the shoe will 
improve the cleaning. Flax, if at all weedy, may be 
run through two sieves below the chaffer. The mis- 
take is often made of trying to run flax through a 



SCIENCE OF THRESHING. 63 

sieve with too small meshes, thus causing it to pass 
over the tailings spout and increasing the impedance 
of the blast. Some kinds of flax have larger seed 
than do others, and this must be remembered in 
adjusting the mill. 

In fast flax threshing, the most satisfactory work 
can be done by using a finishing sieve (of perforated 
sheet metal, not wire) having meshes three-sixteenths 
of an inch across. 



CHAPTER IX. 
BELTS 

The success of a machine depends largely on the 
belts. Their proper care, management and adjust- 
ment are of importance. 

Their material should be of the best quality. If 
leather, they should run with the grain or smooth side 
to the pulley, as they will run more easily, transmit 
more power, and last longer. They will run more 
freely because the flesh or rough side will expand 
more easily and adjust itself to the curve of the 
pulley in running around it, thereby adding to the 
life of the belt. The smooth side will transmit more 
power because it brings more surface into actual 
contact with the pulley. 

Belts should be run just tight enough to perform 
the work without slipping, for power consumed in 
slipping is lost. A belt that slips, tends to partially 
run off the pulley and soon wears out the pulley 
facings. 

If belts become dry and hard, they should have a 
dressing of neatsfoot oil with a little rosin mixed in 
it. Enough rosin should not be used to leave the 
surface of the belt in a sticky condition. A pliable 
belt will transmit more power than a belt that is dry 
and hard. 

Rubber is used quite extensively in some places and 

6 4 



SCIENCE OF THRESHING. 



6 5 



when of the best grade is very economical, as its first 
cost is less than that of the best grades of leather. 
Chain or link belting is sometimes used and in some 
places is preferable to any other. It never slips or 
runs off, and does not become unlaced. When link 
belting is used it should not be run when too tight as 
it causes a trembling or jarring vibration as each link 
passes the sprocket. 

LACING A BELT. 

There is a right and a wrong way to lace a belt. 
The ends to be joined should first be cut squarely 





across. A belt punch to make the holes for the 
lacings should form an aperture big enough for the 
lacing to pass freely without straining the fibre of the 
leather; otherwise there is a tendency to tear out, and 



66 SCIENCE OF THRESHING. 

the lacing to break off. For ordinary work a punch 
making a hole about five-sixteenths of an inch across 
is the most convenient size for ordinary work. A 
smaller one should be used for the holes for the 
lacing ends, which should pass through tightly. 

In punching the holes, care should be taken to 
space them evenly at equal distance from the belt 
edge. An odd number of holes, as three, five or 
seven, according to the width of the belt, gives the 
best result. 

The start should be made by passing the lacing 
ends through the two center holes from the flesh side. 
Then lace from the center once through each hole 
until the belt edge is reached, using one end of the 
lacing for the holes on one side of the center, and the 
other end for the other holes on the other side of 
the center. Then pass the ends of the lace through 
each outside hole again, thence through the suc- 
ceeding holes, until the center is reached. Then pass 
the lace ends up through the small retaining holes. 
By starting as described, it leaves the ends of the lace 
projecting on the pulley side, which prevents them 
from slapping and wearing off as they pass round the 
pulley. It also leaves the belt lacings crossed on the 
pulley face of the belt, thus giving more surface for 
contact. 

When finished the lacing has been passed through 
each hole twice, and is what is called double lacing. 
The lace end should project about three inches when 
finished. Punch the small retaining hole in line with 



SCIENCE OF THRESHING. 67 

the others so that it can be enlarged and used when 
the belt stretches and is cut and relaced. 

Good lace leather of uniform width of about five- 
sixteenths of an inch should be used, with the ends 
tapered for convenience. The smooth side should be 
placed out, as the lace will then last longer. 

Pulleys are crowned or larger in the center to 
cause the belt to run in the center of the pulley. If 
the shafts of two pulleys are parallel, the belt has a 
tendency to run to the large part of the pulleys. If 
the shafts of two pulleys are nearer together at one 
end, the belt when doing work or is tight, has a ten- 
dency to run towards the ends nearest together. If 
one shaft is level and the other high at one end, the 
belt has a tendency to run towards the low end. 
If a belt slips, it will run off on the side of the pulleys 
nearest together. 



CHAPTER X. 
BABBITING BOXES. 

With a little care and practice, anyone of ordinary 
ability can babbitt boxes. 

Babbitt metal is made of block tin and antimony, 
the best grades containing a little copper. Zinc 
should not be used in babbitt as it has a tendency to 
cause the boxes to heat, and besides does not wear 
long. In preparing the box to babbitt, remove any 
old babbitt and clean well, as any grease and moisture 
would, when heated, generate gases and blow the 
molten metal out. Bolt the box in the position for 
which it is intended, as otherwise the tightening will 
throw it out of adjustment and line. 

Place shimming (pieces of pasteboard) between 
the margins of the halves of the box, to allow an 
excess of metal, to allow for wear. In prepar- 
ing this shimming see that its inner edges butt 
against the shaft, in order to separate the babbitt in 
the lower half from the babbitt in the upper half. 
Cut two or three small notches, each about one- 
quarter of an inch long and one-eighth of an inch 
deep, in the edges of the shimming to allow the metal 
to flow through into the lower half of the box, the 
little fins thus formed being readily broken. Hold 
the shaft in place in the box by inserting a leather 
strip wrapped around the shaft at the box end. 

68 



SCIENCE OF THRESHING. 69 

With clay moistened to the consistency of stiff dough 
seal up all the openings thoroughly, save the oil hole. 
Plug this up with a stick, packing the clay around it in 
funnel shape, to pour the metal in. After all is in 
readiness, remove the stick with care that no clay falls 
into the hole. 

To be poured successfully, the metal should be of 
a temperature to burn wood. To test it insert a stick 
of wood occasionally into the melting pot, and when 
the babbitt makes the stick smoke or turn black, it is 
of the right temperature. 

When pouring, the metal should be turned in as 
fast as it will run through the opening, to insure its 
filling the lower half of the box; do not stop until 
the box is full, as the metal chills very quickly and 
will not unite with fresh metal, after it has once set. 

After pouring, remove the clay and break the box 
apart by driving a cold chisel between the halves, 
dressing off the points of the broken fins formed in 
the notches of the shimming. If the lower half of 
the box is not filled, enlarge the openings in the 
shimming and try again. 

Relieve the shaft by scraping some of the babbitt 
from the inside of the box, removing the most near 
the inside edges; in bolting the cap on, insert an 
extra piece of shimming at the box edges, otherwise 
the box would be too tight if left as babbitted, and 
would heat. 

By inserting a stick in the oil hole before the 
metal has cooled, it will form an oil hole and save 
drilling or punching one. 



CHAPTER XL 
LUBRICATION. 

The life of a machine and ease of operation 
depend in a large measure on the manner in which 
its journals are kept lubricated. 

In selecting lubricants keep in mind the purpose 
for which they are to be used. In hot, dry weather 
a thicker and heavier oil can be used than in cold 
weather. In places or bearings subjected to external 
heat, mineral oils are preferable to those containing 
animal or vegetable matter. There is a tendency 
among dealers to supply the cheapest quality of oil, 
which usually proves the dearest to the buyer. 

In many of the machine oils vegetable matter 
mixed with kerosene or other light mineral oil is 
used as it can be sold very cheaply. The kerosene 
soon evaporates at the ends of the journal, leaving 
the vegetable matter in the box where it thickens and 
gums, causing the box to heat or the shaft to run 
hard. Oil of this nature is hard on paint, where it 
spreads out over the woodwork, causing the varnish 
to corrode and become dull. 

A good grade of oil for general purposes is what 
is known as black or crude oil. It is a mineral product 
with all the light oils removed, and may be had of 
different grades of density. The heavier qualities 

7 o 



SCIENCE OF THRESHING. 7 1 

can be used advantageously in warm weather, while 
the lighter grades will be found to run more freely 
in cold weather and do not thicken as easily. 

Hard oils work well in journals when properly 
fed. Cylinder oils should be selected in view of 
standing a high temperature. 

GETTING READY. 

If the machine is one that has been in use the 
previous year, it should be inspected carefully and 
every piece put in proper condition to maintain a 
fall's run, before the time announced as the com- 
mencement of the threshing season. 

See that every box on the machine is properly 
adjusted, the worn ones being set up, and if much 
worn, rebabbitted. A shaft should not be so loose 
in a box as to rattle or move back and forth much, 
neither should it be too tight to run easily. The 
bearings of a shaft which produce or withstand a 
vibrating or oscillating motion, should have special 
attention and not be allowed to get loose, as the least 
play will permit the shaft to pound at each stroke and 
soon wear flat. This will cause the vibrating or 
oscillating part to run or work anything but smoothly, 
and may interfere with its performing its proper 
work. 

The oil cups should be gone over and the vertical 
ones should have a piece of waste inserted to retain 
the oil and keep out the dirt and dust. 

Every belt should be properly laced and stretched 



72 SCIENCE OF THRESHING. 

to the right tension. If a belt is too tight, it is much 
the better plan, instead of overstraining it when 
putting it on, to let out the lacing and then take it up 
when the belt has found its place. If dry and hard, 
a little neatsfoot oil in which a little resin has been 
dissolved will soften a belt and add to its life. The 
rivet heads on the pulley lagging must not project 
for they cut the surface of the belt as it passes over 
them. 

See that every bolt and nut in the machine is in its 
proper place and tightened. If the frame of the 
machine is warped, try to get it in line. Replace 
worn cylinder and concave teeth with new ones. 
Special attention should be given to the straw rakes 
and raddles that they be in good condition. If 
wooden trucks are used, the tires must be examined to 
see if they are tight; if iron wheels are employed, 
every spoke must be screwed up to its proper tension. 

The tool box is an important adjunct to a well 
equipped outfit. It should be provided with the 
necessary tools, such as hammers, wrenches, chisels, 
files, etc., as well as assorted sizes of bolts, screws, 
rivets and nails that are liable to be needed at any 
time. Much valuable time is often saved by being 
able to replace such small parts as are liable to be lost 
or broken. Each tool and article should have a 
place in the box and be kept there, so that it can 
be found when wanted, and will be missed from its 
usual position as soon as mislaid or lost. The box 
must be well covered to exclude all dirt and chaff. 

If the machine be a new one, everything should be 



SCIENCE OF THRESHING. 73 

put in its proper place and all nuts gone over and 
tightened. It is very good practice to leave each nut 
standing square with the piece on which it rests; 
this not only gives the machine a symmetrical and 
workmanlike look, but it accustoms the eye to seeing 
the nuts stand squarely, so that it readily detects any 
change in position due to loosening, and thereby 
allows of instant attention, preventing loss. Remove 
all cinders and dirt from the boxes and running parts 
and pack them with waste, as before stated, to 
exclude all foreign substances. Finally, before assem- 
bling the crew, run the machine empty for a time to 
see that all the parts are properly adjusted; this 
gives a chance also to adjust the belts, which when 
new, stretch after being run a short time. 



CHAPTER XTT. 

THE CREW. 

It is the duty of the manager to see that everything 
is operating properly; look after the welfare and 
comfort of the crew and see that each performs the 
task assigned him; economize time and keep the 
expense down so as to accomplish the most work with 
the least outlay; and in general, lay out and plan 
the work so that there is no waste of time either on 
the part of the machine or the men attending it. 
Much of the success of the machine depends upon 
this. 

To make the machine do its best, it is necessary that 
each man should perform his part; this should be 
seen to by the manager and the allotment of work 
should be under his exclusive control. There is no 
place where there is greater necessity for a head and 
leader than around a threshing machine. The man- 
ager should assert his rights in a firm and mild man- 
ner, should never lose his temper or show anger, 
should not abuse any one or permit any bullying 
among the crew. It is very demoralizing to have a 
bully among the crew, especially if he be permitted to 
exercise his inclinations on his fellow workmen. Har- 
mony in the crew rests largely with the manager, and 
he should see to proper adjustment there as well as in 
the machine itself. 

74 



SCIENCE OF THRESHING. 75 

The feeders should be sufficiently acquainted with 
the machine to be able to work in harmony with it, 
in order that the work progress successfully. The 
motion and working of the machine should be 
watched by them so that any faults may be corrected. 

It is good practice, and usual in hand feeding, for 
each to take his turn, one feeding a given time or 
amount of grain, and then being relieved by the 
other. The feeder is the one who is depended upon 
to regulate the amount to be threshed and the quan- 
tity of grain cleaned per day depends on him in 
a large measure. 

The feeding should be even and continuous and at 
as constant and steady a rate as possible at all times, 
in order that the crew may become accustomed to the 
average amount of straw and grain to be handled, 
and so be able to judge of the labor required of them. 
The motion of the one feeding should be adapted to 
the kind and condition of the grain to be threshed. 
The more the straw is divided and spread out, the 
less power will be consumed in passing it through the 
cylinder. When the power is limited, as in threshing 
with horses, this fact should be well borne in mind. 

In steam threshing, where more grain is being 
handled and there is plenty of power, the feeder has 
about enough to do to keep the bundles passing in 
without spending much time in spreading them out. 
He should, however, feed as continuously as possible 
in order that a bundle may be engaged and drawn in 
by the cylinder before the preceding one has passed 



76 SCIENCE OF THRESHING. 

entirely through. This aids in lessening the amount 
of power required. 

The band cutters should cut the bands and pass the 
bundles to the feeder in such a way as will aid him in 
doing his work. To assist the free moving of the 
bundles across the table, it should be kept clear of 
clinging straws. Care should be taken in the use of 
the knife used to cut the bands, as many a feeder has 
had his hand cut by inattention or carelessness on the 
part of the band cutter. Each band cutter should 
become accustomed to one side of the machine and 
always work there, as he can perform his work better 
than if he changes about. 

The pitchers are depended upon to get the un- 
threshed grain to the machine as fast as needed in a 
way that will facilitate the work. There should be 
enough pitchers provided so that the machine will 
not have to wait for grain or run partly empty, as this 
will cause some of the rest of the crew to stand idle 
and will curtail the earnings of the machine for the 
day's run. 

It is good practice for each man to keep his partic- 
ular position on one side of the machine for the 
entire time he is with it. He thus becomes accus- 
tomed to handling the bundles in a certain way on 
that side, while on the other, the position and move- 
ments are reversed. The work will be performed 
with greater expedition and ease as the muscles 
become accustomed to certain movements. 

The straw crew takes care of the straw as fast as it 
is delivered from the carrier. 



SCIENCE OF THRESHING. 77 

It is as easy to form and build a good, symmetrical 
stack, as to push the straw back without reference to 
the form of the pile. If the stack be commenced well 
up towards the machine so that the stacker drops the 
straw near the center of the stack; the straw will not 
have to be moved as far as if the carrier deposited it 
at the edge of the stack; in the latter case the straw or 
part of it, would have to be moved the entire width 
of the stack. Also, if the center be better tramped 
than the edges, the latter will settle more so that the 
straw will incline downward on the outside, making 
a better watershed; if the bulk of the straw has to 
be moved from the center of the stack, as happens 
when the stacker delivers there, the straw men will 
naturally stand there, thereby packing it closely. 



CHAPTER XIII. 

WASTING GRAIN 

There is no place on earth where a kernel of grain 
looks as large and is of so much value as at the tail 
end of a machine. To see some hunt and search for 
them, one would think each one a diamond or priceless 
gem. There is no time when a farmer is so careful 
of his property as right then. Any amount may be 
wasted by the harvester or in handling the grain, but 
let him discover a few kernels going into the straw 
through the separator and he at once loses his reason 
and imagines ruin stares him in the face. He will 
show them to the operator with an autocratic air of 
"do better or quit." 

In a bushel of oats, 32 lbs., there are about 
600,000 kernels. In a bushel of wheat, 60 lbs., 
there are about 1,000,000 kernels. If the farmer 
should hold his hand where the grain is wasting 
fastest for half a minute, and should catch ten kernels, 
he would say that half of it was going in the straw. 
Let us see. Counting 26 days for a month and 
10 hours for a day, it would take him over three 
months to catch a bushel of wheat. Oh, yes, he 
says, but he only held his hand under a small 
part of the falling chaff. Well, suppose the ma- 
chine was 52 inches wide and his hand only two 

78 



SCIENCE OF THRESHING. 79 

inches, and the grain wasting equally across the 
entire width, it would then take three days at the 
same rate for enough kernels to pass to fill a bushel 
measure. 

In order to waste five bushels in a day of ten hours' 
run, there would have to be 138 kernels escape every 
second or 8,240 every minute. It is very deceiving 
when the quantity of grain comes to be measured by 
the kernel. While most threshers are willing to do 
all in their power to save the grain for their cus- 
tomers, the farmer should remember that absolute 
perfection is impossible, and that the actual waste is 
but very small as compared to the amount threshed. 

It is difficult to state what per cent, a machine may 
waste and still be doing reasonably good work. 
There have been several tests made to determine this, 
but the conditions varied so that there are scarcely 
two reports alike. In ordinary threshing, when the 
conditions are not unfavorable and the machine is not 
being over crowded, it should not waste more than 
one-third of one per cent; this will be only a little over 
three bushels per thousand. Calling 10 hours one day, 
and threshing 1,000 bushels, to waste three bushels 
would necessitate losing all which would lay on 
the palm of the hand, every 15 seconds, not a very 
long space of time, only a quarter of a minute. This 
would show very plain and the machine would appear 
to be wasting very fast. If the kernels are still in the 
head, unthreshed, the waste may be in much larger 
proportion; a kernel in every head or two soon 
counts up. 



PART II. 



TRACTION and 

PORTABLE 

ENGINES 



INTRODUCTION. 

The conditions which arise in the operation of the 
engine of an up-to-date threshing outfit demand a 
thorough knowledge of the principles which underlie 
its workings. 

The following pages are designed to explain the 
principles on which practical and economical opera- 
tions of traction engines are based. 



GENERAL THEORY OF THE GENERA- 
TION OF STEAM 

CHAPTER I. 
HEAT 

The generation of steam from water depends upon 
the expenditure of heat. It is well to understand 
what is meant by the term heat. 

Heat is a form of energy. It is in fact a mode of 
motion among the particles or molecules which com- 
pose matter. If the molecules are moving or 
vibrating back and forth among themselves, the 
sensation of heat is produced. This term is only 
relative; what seems cold to one person is hot to 
another; but if we start from a common basis we 
may say that a high rate of vibration in the mole- 
cules produces heat. A low rate produces a very 
much less degree of heat, which we are used to 
calling cold. Inasmuch as any body in motion is 
capable of overcoming resistance, that is, doing work, 
we say that it has kinetic energy; therefore, the mole- 
cules which are vibrating to produce the effect called 
heat possess this energy, and hence, we are right in 
saying that "heat is a form of energy." 

In other words, the molecules of a heated body 

83 



84 SCIENCE OF THRESHING. 

do work just as truly as does a man who shovels dirt. 

The more heated the body is, the faster do the 
molecules vibrate, and the more work can they do, or 
the more energy they have. 

Temperature is a term used to denote the rate of 
vibration of the molecules of a heated body. It does 
not express the quantity of energy which a body has, 
but it does express the way in which the molecules are 
vibrating. Thus, a body having a high temperature 
is said to be hot; a body having a low temperature is 
said to be cold. The temperature of a small piece 
of iron may be very high, yet it does not have as 
much heat as a large piece which may be of the same 
temperature. 

Bearing these facts in mind, and especially that 
heat is but a form of energy, or work, let us see how 
it is made to do work, such as running a threshing 
machine. 

A heated body may impart the energy of its 
moving molecules to an adjacent body, or, commonly 
speaking, heat it. If the heated fuel in the boiler 
fire-box communicates its heat, its power to do work, 
its energy, to the walls of the box and shell of the 
boiler, the latter may in turn, heat or energize or 
impart the power to do work, to heat water in the 
boiler. When you heat water, its temperature rises, 
that is, its molecules commence to vibrate faster and 
faster. When the temperature reaches 212 degrees, 
a change occurs in the vibration of the molecules. 
Their rate of vibration does not increase, but the 
length of vibration increases, the molecules tending 



SCIENCE OF THRESHING. 85 

to move farther apart. This causes the body of 
water as a whole to expand. Another effect of heat 
is still further exemplified in the expansion of railroad 
rails in summer, the expansion of tires for setting, 

etc. 

In other words, the molecules of a substance which 
is heated, are just as capable of doing work is an 
able-bodied man armed with a shovel. 

If heat is applied after water in an open vessel 
has reached a temperature of 212 degrees, the 
temperature of the water does not change, but 
instead, the extra energy imparted has resulted 
in making the molecules increase their length of 
vibration as well as their rapidity. The molecules 
have lost their power of inter-attraction or cohe- 
sion, and are attempting to fly apart or expand. 
In other words water at the temperature of 
212 degrees at atmospheric pressure changes from 
a liquid to a gas, and this gas, if allowed to 
expand fully, occupies 1,700 times the volume 
or space which the water did. This gas is 
known as steam. This energizing of water or 
putting its particles or molecules into motion, this 
generating of steam, is accomplished by heating it. 
As before said, if then this heat has imparted a power 
to do work, it is evident that a certain amount of heat 
must impart a certain ability to overcome resistance, 
a certain energy, and vice versa, the energy will 
produce a certain amount of heat. 

If the water is confined so that it cannot expand, 
as in a boiler, and extra heat be applied, the tempera- 



86 SCIENCE OF THRESHING. 

ture will continue to rise. If the molecules cannot 
increase the length of their vibration, they increase the 
number of vibrations. When heat is applied, water 
either expands or rises in temperature. Expanded 
water or steam is of the same temperature as the 
water from which it is made. It contains more 
energy but is of the same temperature. 



CHAPTER IT. 



LATENT HEAT 



This excess energy— heat— which is used in 
turning the water into steam and which the thermom- 
eter does not register is termed "Latent Heat." 
Latent comes from the Latin word meaning "con- 
cealed" or "hidden" and hence is very appropriate. 

If we place water in a cylinder, the lower end of 
which is closed, and bring a sliding piston down on 
it, we may heat the water to the 212 degree point and 
not see that any appreciable change has taken place. 
If, however, we continue to impart heat to the water 
the thermometer does not show an increase, provided 
that the piston be not too heavy. Roughly speaking, 
as long as the piston is free to move the water does 
not rise in its temperature ; that is, the specific heat 
does not increase, but the latent or non-apparent heat 
does. As a result the energy of vibration of the 
molecules increases to such an extent that the water 
or steam increases in volume 1,700 times; and as a 
consequence the piston must move or force must be 
applied to the other side to hold it in place against 

the steam. 

In other words, the heat which has been given to 
the water, or the energy, or work-doing power, has 
so set its molecules vibrating that their motion has 

87 



88 SCIENCE OF THRESHING. 

become appreciable and that they are capable of 
doing work of a kind that can be used. 

Now if the heat given to water when it is turned 

into steam is capable of making the steam do work, 
there must be a certain quantity of heat which will 
do a certain amount of work. The standard by 
which we measure heat is known as the British Ther- 
mal Unit; or, as commonly abbreviated, the B. T. 
U. This is the quantity of heat which is required to 
raise one pound of water one degree in temperature. 
Careful experiment has demonstrated that you must 
impart at least one B. T. U. of heat to water after 
the 212 mark is passed to enable the steam to lift one 
lb. in weight 778 ft., or 10 lbs. in weight 77.8 ft., or 
100 lbs. in weight 7.78 ft. In other words, one B. T. 
U. is equivalent to 778 foot-pounds, and you thus 
have the energy which is expended by the vibrating, 
moving molecules of the water to which heat has 
been applied, measured by something which all can 
understand, and which is the common term to denote 
the pull required on the driving belt of the separator. 

It has been found that the burning of one pound 
of coal gives out sufficient heat to raise the tempera- 
ture of 14,000 lbs. of water from 62 to 63 degrees, 
or in the language of heat, the coal gives out 
14,000 B. T. U. One B. T. U. can raise 778 lbs. 
one foot, or is equivalent to 778 foot-pounds. There- 
fore, one pound of coal can raise 14,000 X 778, or 
10,892,000 foot-pounds; this amount of power 
would raise 7,000 lbs. 1,556 feet. 



SCIENCE OF THRESHING. 89 

The burning of the fuel in the fire-box of the 
boiler causes the molecules of the fuel to start 
vibrating at a high rate of speed, or to rise to 
a high temperature. This energy of motion in the 
molecules is communicated to the surrounding air 
and to the walls of the fire-box. Obviously it is 
necessary to see that as much of this energy as pos- 
sible be saved or rather directed to the point where it 
can be used, and so the fire-box of the boiler should 
be such as will best retain the heat and best transmit 
it to the water in the boiler. 

We have further seen how the heat affects the 
water to which it is imparted through the walls of the 
fire-box, and as a final step in our reasoning, we have 
seen how the vibration of the molecules of the water 
finally overcomes that mysterious force which tends 
to hold them together as water, and causes them to fly 
apart or expand. This power of expansion we make 
to do work by putting something in the way of the 
expanding particles which they must move before 
they can go as far as they otherwise would, and we 
thus turn the energy of the vibrating molecules of the 
burning fuel into an energy which we can harness and 
direct as we please. 

It will be remembered that when water was heated 
to 212 degrees, the temperature remained the same, 
while the heat which was afterwards applied disap- 
peared as far as the thermometer was concerned, and 
this we called hidden or latent heat. It is found by 
careful experiments that it takes about 144 units of 



90 SCIENCE OF THRESHING. 

heat or B. T. U. to change a pound of ice to water at 
32 degrees. It is found that it takes a quantity of heat 
expressed by about 966 B. T. U. to change one pound 
of water into steam, and this, therefore, is 966 times 
as much heat as is required to raies a pound of water 
from 62 to 63 degrees. Thus the latent heat o fsteam 
or amount of energy which is transmitted to steam at 
a temperature of 212 degrees is about 966 B. T. U. 
At different temperatures, the latent heat of steam 
differs. The heat which is taken into the water when 
it changes from water to steam is given off again 
when it condenses or turns back to water. 



CHAPTER III. 
COMBUSTION OF COAL 

When coal is exposed to heat in a furnace, a por- 
tion of the carbon and hydrogen, associated in 
various chemical unions as hydrocarbons, are vola- 
tilized and passed off. At a low temperature, 
naphthaline, resins and fluids with high boiling points 
are disengaged; at a higher temperature, volatile 
fluids are disengaged; and at still higher, olefiant 
gas, followed by common gas, light carburetted 
hydrogen, which continues to be given off after the 
coal has reached a low red heat. What remains after 
the distillatory process is over, is coke, which is the 
fixed or solid carbon of coal, with earthy matter, the 
ash of the coal. 

TABLE NO. I. 

Taking the fixed carbon, or coke remaining in the 
furnace after the volatile elements are distilled off, 
at 60 per cent., in round numbers, the following is 
an approximate summary of the condition of the 
elements of average coal, after having been decom- 
posed, and prior to entering into combustion : 

100 POUNDS OF AVERAGE COAL IN THE FURNACE 
Composition. Lbs. Decomposition. Lbs. 

Carbon Fixed 60 Fixed Carbon 60 

Carbon Volatilized 20 Hydrocarbons 24 

Hydrogen 5 Sulphur 1 1/4 

Sulphur 1 1/4 Water or Steam 9 

Oxygen 8 Nitrogen 1 1/5 

Nitrogen 1 1/5 Ash 4 

Ash 4 



100 



About 100 



9 1 



9 2 



SCIENCE OF THRESHING. 



This shows a total useful combustible of 86^4 P er 
cent., of which 26% P er cent, is volatilized. While 
the decomposition proceeds, combustion proceeds, and 
the 2634 P er cent, of volatilized portions, and the 
60 per cent, of fived carbon, are successively burned. 



TABLE NO. 2. 



Total heat evolved by 'various fuels and their 
equivalent evaporative power, with the weight of 
oxygen and volume of air chemically consumed. 



Fuel. 



<v - 



<M 



> 3D u 



Quantity of Air 

Consumed per Tb . of 

Fuel. 




Lbs. 



Lbs. 



Cu. ft. 
at 62°. 



Heat Unit. 



Lbs. 



Hydrogen 8.0 34.8 457 62000 62.40 

Carbon, making Car- 
bonic Acid 2.66 11.6 152 14500 15.0 

Sulphur 1.00 4.35 57 4000 4.17 

Coal, av. dessicated. . .2.45 10.7 140 14700 15.22 

Coke, av. dessicated. .. 2.49 10.81 142 13548 14.02 

Lignite, perfect 2.04 8.85 116 13108 13.57 

Asphalt 2.74 11.85 156 17040 17.64 

Wood, dessicated 1.40 6.09 80 10974 11.36 

Wood, 25 % moisture. .1.05 4.57 60 7951 8.20 

Straw, 15%% moisture. 0.98 4.26 56 8144 8.43 

Petroleum 3.29 14.33 188 20411 21.13 

Petroleum Oils 4.12 17.93 235 27531 28.50 



SCIENCE OF THRESHING. 



93 



TABLE NO. 3, 



Silver 1000 

Copper 850 

Gold 800 




Boiler Scale 

Brick 

Soot 



60 
11 

10 



The above table shows the relative heat conducting 
power of different substances. 

The fact that soot and boiler scale are such poor 
heat conductors shows how essential it is that the fire- 
box and flues should be kept free from soot and the 
boiler from scale, to give the action of the fire free 
access to heat the water. An ordinary threshing 
engine will give from two to four horse power more, 
when clean of soot and scale than where dirty. 

TABLE NO. 4. 

The following table shows the chemical composi- 
tion of ordinary firewood. 

Carbon 37.5 per cent. 

Hydrogen 4.5 per cent. 

Oxygen 30.75 per cent. 

Nitrogen 0.75 per cent. 

Ashes 1.5 per cent. 

75.0 per cent. 
Hygrometric water 25.0 per cent. 

100.0 



94 SCIENCE OF THRESHING. 

TABLE NO. 5. 

conditions, is about as follows : 

The composition of straw in its ordinary air-dried 

Wheat Straw, Barley Straw, Mean, 

Per cent. Per cent. Per cent. 

Carbon 35.86 36.27 36.075 

Hydrogen 5.01 5.07 5. 

Oxyken 37.68 38.26 38. 

Nitrogen 45 .40 .425 

Ashes 5.00 4.50 4.75 

Water 16.00 15.50 15.75 

100.00 100.00 100.00 

TABLE NO. 6. 

1 Cord hickory or hard maple weighs 4,500 lb. equals 2,000 lbs. coal. 

1 Cord white oak weighs 3,850 lbs. equals 1,711 lbs. coal. 

1 Cord beech, red or black oak weighs 3,20 lbs. equals 1,445 lbs. coal. 

1 cord popuar, chestnut or elm weighs 2,350 lbs. equals 1,044 lbs. coal. 

1 Cord average pine weighs 2,000 lbs. equals 890 lbs. coal. 

1 Ton dr ystraw weighs 2,000 lbs. equals 1,110 lbs. coal. 



CHAPTER IV. 

PROPERTIES OF STEAM 

If we heat water in an open vessel, it soon reaches 
the temperature of 212 degrees. If we continue to 
heat it, it boils, or the energy imparted to its mol- 
ecules is such that their vibrations become violent 
enough to cause them to fly oft and thus the vapor or 
steam arises. If we now close the top of the vessel, 
the molecules in their attempt to escape encounter 
resistance and hence have to expend some of their 
energy in overcoming this, that is, an extra quantity of 
heat must now be given to the water to make it turn 
to steam. If it rests under the weight of the atmos- 
phere alone, or about 14 lbs. to the square inch, the 
water will boil at 212 degrees. If the pressure be 
increased to 32 lbs., the water will not boil until it 
reaches a temperature of 254 degrees. If the pres- 
sure be diminished to about six lbs. to the square inch, 
the boiling point is about 170 degrees, hence the law 
or general statement: An increase of pressure on 
the surface of a liquid raises the temperature at which 
it boils; a decrease of pressure lowers the tempera- 
ture. The temperature of boiling w r ater always cor- 
responds to its pressure. We call steam which is in 
contact with the surface of water, saturated steam. 
Under the law just given, its temperature depends on 
the pressure in the boiler. 

95 



CHAPTER V. 

SATURATED STEAM AND ITS 
PROPERTIES. 

Temperature is not the only property of saturated 
steam which changes with the pressure. Other char- 
acteristics also change. These may be stated briefly 
as follows : 

i. — The amount of heat which is required to raise 
a pound of water from 32 degrees, or freezing, to the 
point at which it boils or steams at a given pressure. 
That is expressed, of course, in the only term we have 
to measure latent heat, in B. T. U., and is called the 

HEAT OF THE LIQUID. 

2. — The amount of heat which is required to 
change water at the temperature at which it boils into 
steam of the same temperature. This is called 

LATENT HEAT OF EVAPORIZATION, OR LATENT 

heat. This, too, is expressed in B. T. U. 

3. — The total amount of heat required to change 
a pound of water at 32 degrees to steam of the 
required temperature and pressure. This is called 

the TOTAL HEAT OF EVAPORIZATION, or simply, 
TOTAL HEAT. 

It is plain that the total HEAT is the sum of the 

LATENT HEAT plus the HEAT OF THE LIQUID. 

4. — The number of cubic feet occupied by a pound 

96 



SCIENCE OF THRESHING. 97 

of steam at the given pressure; or the specific 
volume. 

5- — The density of the steam; that is, its weight 
per cubic foot at the required pressure. 

All these properties may be collected in a table so 
as to be readily seen and this is known to engineers 
as the steam table. 



98 SCIENCE OF THRESHING. 

STEAM TABLE. 

TUB PROPERTIES OF SATURATED 
STEAM. 



a 


Temperature, Fahrenheit 
Degrees. 


Quantities <>f Heat in British 
Thermal Units. 


Weight of a Cubic Foot of 
Steam in Pounds. 


Volume. 


3 
o <0 

• * ™ 

>-* 3 

> tn 

2 u 

rt ft 

3 c 

<U O 


« 

4J 3 E 
S 2 

_ c, 1 - 
_ ^ 

Pi 


*-> 

a 
w 

n) 

*j 4) 
C 3 

1-1 u 




CO 

> 
O 
43 

1) 



H 


E 

s . 

£% 

0^ 

■e-1 

c -2 
3 P 
ou 

*a 
rt ,p « 

O 


E ci>, 
cr£ § 

>gS| 

•2 *J'«5 

04 ofl^ 


I 


2 


3 


4 


5 


6 


7 


8 


P 


t 


'/ 


I. 


// 


w 


F 


A' 


I 

2 

3 

4 
5 

6 

7 
8 

9 

IO 

i i 

1 2 
13 
14 

I4.69 

'5 
l6 

'7 

18 

'9 


162.018 

1 26.302 
141.654 
153.122 
162.370 

170.173 

'76.945 
182.95a 

188.357 
[93.284 

[97.814 

202.01 2 
205.929 
209.604 

2 1 2.000 

2 13.067 
216.347 
219.452 

222.424 

225.255 


70.040 

94.368 

109.764 

1 21. 271 

'30.563 

138.401 
'45-213 
'5'-255 
156.699 
161. 660 

166.225 
170.457 
174.402 
178.112 

180.531 

[81. 60S 
[84.919 
[88.056 

[91.058 
193.918 


"1043.01 5 
IO26.O94 
IOI5.380 
IO07.370 
IOOO. S99 

995-441 
990.695 
986.485 
982.690 
979.232 

976.050 
973.098 
970.346 

967-757 

966.069 
965-3'8 

<;<>.v 00 7 

960. 8 1 8 

958.721 
956.725 


'"3-055 
1 120.462 
. 125.144 
1 1 28.641 
1 131.462 

1133.842 
1 135-908 
1137.740 
1 [39.389 
1 140. 892 

1142.275 

"43-555 
1144.748 
1145.869 

1 1 46.600 

1 1 46.926 
1 147.926 
[ 148. 874 

1149.779 
1150.643 


.003027 
.005818 
.008522 
.011172 
.013781 

•016357 
.018908 
.021436 

•023944 
•026437 

.02891 1 
.031376 
033828 
■036265 

.037928 

.0386SS 
.041 109 

■0435 J 9 
,045920 
.048312 


330.4 
171.9 

"7-3 
89.51 

72.56 

61.14 
52.89 
46.65 
41-77 
37-83 

34-59 
31-87 
29.56 

27.58 
26.37 

25-85 

24-33 
22. 98 

21.78 

20. 70 


20623 
10730 

7325 
5588 
4530 

3816 
3302 
291 2 
2607 
2361 

2 159 
1990 

1845 
1 72 1 

1 646 

1 6 1 4 

'5'9 
'434 
'359 
1292 



SCIENCE OF THRESHING. 



99 



I 


2 


3 


4 


5 


6 


7 


8 


p 


t 


7 


L 


H 


W 


V 


R 


20 


227.964 


196.655 


954,8i4 


1 15 1.469 


.050696 


1973 


1231.0 


22 


233.069 


201.817 


951.209 


1153.026 


•055446 


18.04 


1126.0 


24 


237.803 


206.610 


947.861 


1154.471 


.060171 


16.62 


1038.0 


26 


242.225 


21 1.089 


944-73° 


ii55-8i9 


.064870 


15-42 


962.3 


28 


246.376 


215.293 


941.791 


1157.084 


•069545 


14.38 


897.6 


3° 


250.293 


219.261 


939.019 


1158.280 


.074201 


13.48 


841.3 


32 


254.002 


223.021 


936.389 


1159.410 


.078839 


12.68 


791.8 


34 


257-523 


226.594 


933-89I 


1 160.485 


.083461 


11.98 


748.o 


36 


260.883 


230.001 


93i-5o8 


1161.509 


.088067 


11.36 


708.8 


33 


264.093 


233.261 


929.227 


1162.488 


.092657 


10.79 


673-7 


40 


267.168 


236.386 


927.040 


1 163.426 


.097231 


10. 28 


642.0 


42 


270. 122 


239-389 


924.940 


1164.329 


.101794 


9.826 


6i3-3 


44 


272.965 


242.275 


922.919 


1165.194 


.106345 


9-403 


587-0 


46 


275.704 


245.061 


920.968 


1 166.029 


.110884 


9.018 


563-0 


48 


278.348 


247.752 


919.084 


1166.836 


.115411 


8.665 


540.9 


5° 


280.904 


2 5o.355 


917. 260 


1167.615 


.119927 


8.338 


520.5 


52 


283.381 


252.875 


9 J 5-494 


1168.369 


•124433 


8.037 


5 OI -7 


54 


285.781 


255-32I 


913.781 


1169. 102 


.128928 


7-756 


484.2 


56 


288. in 


257.695 


912. 118 


1169.813 


•133414 


7-496 


467.9 


58 


290.374 


260.002 


910.501 


1170.503 


.137892 


7.252 


45 2 -7 


60 


292-575 


262:248 


908.928 


1 171. 176 


.142362 


7.024 


438.5 


62 


294.717 


264.433 


907.396 


1171.829 


. 146824 


6. 811 


425.2 


64 


296.805 


266.566 


905.900 


1172.466 


.151277 


6.610 


412.6 


66 


298.842 


268.644 


904.443 


1173.087 


•I5572I 


6.422 


400.8 


68 


300.831 


270.674 


903.020 


1173.694 


.160157 


6.244 


389.8 


70 


302.774 


272.657 


901.629 


1174.286 


.164584 


6.076 


379-3 


72 


304.669 


274-597 


900. 269 


U74-866 


.169003 


5-917 


369-4 


74 


306.526 


276.493 


898.938 


"75-431 


• I734I7 


5-767 


360.0 


76 


3°8-344 


278.350 


897.-635 


"75-985 


.177825 


5.624 


35 1 - 1 


7? 


310.123 


280. 170 


896.359 


1176.529 


. 182229 


5.488 


342.6 


80 


311.866 


281.952 


895.108 


1177.060 


.186627 


5-358 


334-5 


82 


3r3-576 


283.701 


893.879 


1177.580 


. 191017 


5-235 


326.8 


84 


315-25° 


285.414 


892.677 


1 178.091 


.195401 


5.118 


3*9-5 


86 


316.893 


287.096 


891.496 


1178.592 


.199781 


5.006 


3"-5 


88 


318.510 


288.750 


890-335 


1179.085 


•204155 


.4.898 


305-8 



IOO 



SCIENCE OF THRESHING. 



I 


2 


3 


4 


5 


6 


7 


8 


p 


/ 


q 


L 


H 


W 


V 


R 


90 


320.094 


290.373 


889.196 


1179.569 


.208525 


4.796 


299.4 


92 


321.653 


291.970 


888.075 


1180.045 


.212892 


4.697 


293.2 


94 


323- 18 3 


293-539 


886.972 


1180.511 


•217253 


4- 603 


287.3 


96 


324.688 


295.083 


885.887 


1180.970 


. 221604 


4-5I3 


281.7 


9 8 


326. 169 


296.601 


884.821 


1181.422 


.225950 


4.426 


276.3 


IOO 


327.625 


298.093 

3° I -73 I 


883.773 


1181.866 


•230293 


4-342 


271. 1 


10S 


33 I - I 69 


881.214 


1182.945 


.241139 


4.147 


258.9 


1 10 


334-5 82 


305-242 


878.744 


1183.986 


.251947 


3-969 


247.8 


"5 


337-874 


308.621 


876.371 


1184.992 


.262732 


3.806 


237.6 


120 


34i-°5 8 


311.885 


874.076 


1185.961 


.273500 


3-656 


228.3 


125 


344-I3 6 


315-051 


871.848 


1186.899 


•284243 


3-5^8 


219.6 


130 


347-I2I 


318.121 


S69.688 


1187.809 


. 294961 


3-39° 


21 1.6 


i35 


3SO-OI5 


321105 


867.590 


1188.695 


•305659 


3.272 


204.2 


140 


35 2 -827 


324.003 


865-552 


"89-555 


•316338 


3. 161 


197-3 


M5 


355-5 6 2 


326.823 


863.567 


1 190.390 


•326998 


3-058 


190.9 


*5° 


358-223 


329.566 


861.634 


1191.200 


•337643 


2.962 


184.9 


160 


363-346 


334-850 


857.912 


1192.762 


.358886 


2.786 


173-9 


170 


368.226 


339-892 


854-359 


1194-251 


.380071 


2.631 


164.3 


180 


372.886 


344.708 


850.963 


1195.671 


.401201 


2-493 


r 55-6 


190 


377-352 


349-329 


847-703 


1197.032 


.422280 


2.368 


147.8 


200 


381.636 


353-766 


844-573 


H98.339 


•4433 10 


2.256 


140.8 


210 


385-759 


358.041 


841.556 


"99-597 


•464295 


2.154 


134-5 


220 


389-736 


362.168 


838.642 


1200.810 


•485237 


2.061 


128.7 


230 


393-575 


366.152 


835.828 


1201.980 


.506139 


1.976 


123-3 


240 


397-285 


370.008 


833- 103 


1203. hi 


.527003 


1.898 


M8.5 


250 


400.883 


373-75o 


830.459 


1204.209 


547S3I 


1.825 


1 14.0 


260 


404.370 


377-377 


827.896 


1205.273 


568626 


i-759 


109.8 


270 


407-755 


380.905 


825.401 


1206.306 


589390 


1.697 


105.9 


280 


411.048 


384-337 


822.973 


1207.310 


610124 


1.639 


102.3 


290 


414.250 


387.677 


820.609 


1208.286 


630829 


i-585 


99.0 


300 


4i7-37i 


390.933 


818.305 


1209.238 


651506 


i-535 


95-8 



SCIENCE OF THRESHING. lOI 

EXPLANATION OF THE TABLE. 

Column i gives pressures of from one to three 
hundred pounds. These are not gauge pressures 
obtained by reading the gauge, as these do not include 
the pressure of the atmosphere, which is about 14.7 
lbs. per square inch. The gauge is set to register 
zero when there is nothing but the air pressing on the 
water in the boiler, and hence 14.7 lbs. must be 
added to all guage readings to obtain these absolute 
pressures. 

Column 2 gives the temperatures to which the 
steam rises when at the pressures of column 1. 

Column 3 gives the heat of the liquid, or the 
number of B. T. U. required to raise a pound of 
water from 32 degrees to the boiling point corres- 
ponding to the given pressure, or the amount of 
energy which goes to do this work. 

The values in column 3 may be closely approx- 
imated by subtracting 32 degrees from the tempera- 
ture in column 2. This is not strictly correct for all 
values, as the specific heat of the water, instead of 
remaining at a constant, increases slightly. 

Column 4 gives the latent heat of evapori- 
zation. This is the amount of energy which is 
absorbed in changing water from the boiling point 
to steam of the same temperature as the boiling 
point of the water, and is measured again in the very 
useful B. T. U. 

Column 5 gives the total heat of evaporiza- 
TION, and may be obtained by adding the corres- 
ponding values of columns 3 and 4. 



102 SCIENCE OF THRESHING. 

Column 6 gives the specific volume of a pound 
of steam at the given temperature or pressure, which 
is expressed in pounds, being the weight of a cubic 
foot of steam at the pressure given. 

Column 7 gives the number of cubic feet occupied 
by one pound of steam at the given temperature, or 
its specific volume. 

Column 8 gives the ratio of the volume of a pound 
of steam at a given pressure to the volume of a pound 
of water at the temperature of 39.1 degrees. This is 
equal to the weight of a cubic foot of water at 39.1 
degrees, or 62.425 lbs., divided by the weight of a 
cubic foot of steam of the required or given pressure, 
as found in column 6. 

We have thus followed the results of the applica- 
tion of heat to water and found that it is but the 
taking of the energy of an already heated body, as 
the fuel in the fire-box of the boiler, and transmitting 
it to the molecules of the water, or, as better 
expressed, it is transmitting the rapid vibrations of 
the molecules of the fuel to the molecules of the 
water until the latter are moving at such a rapid rate 
and with such a swing that they overcome cohesion, 
that mysterious attraction which particles of one 
kind of matter have for each other, and tend to fly 
apart, or as we say, expand, and this at a tremendous 
rate. 

By taking advantage of this appreciable movement 
of the molecules, we are able to do work or overcome 
resistance with them, 



CHAPTER VI. 
THE BOILER 

A steam boiler is an apparatus in which heat is 
transferred from burning fuel to water; where the 
energy of the vibrating molecules of the burning fuel 
is transferred to the molecules of the water, until the 
motion of the latter becomes so violent as to cause 
the mass or volume of steam to expand with a force 
which can be readily harnessed for use. 

A boiler consists of the fire-box, in which the 
combustion takes place, the water space, in which the 
water is heated through contact with a heating sur- 
face which surrounds the fire-box, passages to conduct 
away the smoke and other products of combustion, 
and various accessories to furnish water and regulate 
the heat, etc. We have seen what a little loss of heat 
means in the way of loss of energy, or power to do 
work, and therefore the fire-box should be constructed 
to direct as much of the heat of the flames and 
burning gases to the surface against which the water 
lies as possible; there should be no "dead" corners 
where there is a loss of heat, and the smoke passages 
should be so disposed as to utilize the heat from the 
escaping gases. 

Boilers for traction engines may be roughly 
divided into three classes: The locomotive boiler, 
the return flue boiler, and the vertical or upright 

103 



I04 



SCIENCE OF THRESHING. 



boiler. The locomotive boiler is so called from its 
resemblance to the type used in locomotive practice. 

Its parts are, first, a rectangular fire-box, a, held in 
position in the shell of the boiler by stay bolts, c. 

Second, the waist, a cylindrical portion, d, through 
which pass the tubes or flues, e, connecting the fire- 
box with the smoke box, /. 

Third, the steam dome, g, from which the steam 
may be taken. 




ILLUSTRATION IN SECTION OF BOILER. 



The flat portions of the boiler above the fire door 
and over the front ends of the flues are stayed by 
long rods called stay rods. The crown sheet over 
the fire-box is supported by stay bolts. 

In a return flue boiler, the fire box extends the 
whole length of the boiler, which is usually tubular, 
and the flues come back through the shell returning 
the smoke to the fire door end. 



SCIENCE OF THRESHING. 



IO5 




The vertical type comprises merely a vertical, 
cylindrical shell with vertical flues and fire-box under 
them. 

The main object in the distribution and arrange- 
ment of the parts are twofold. First, direction of the 
heat of the fuel against spaces or walls the other side 
of which are in contact with the water, so that the 
energy of the burning fuel may not be dissipated or 
wasted on the outer air, or outer parts of the boiler. 
Second, presenting as large a surface of water as 
possible to the heated surfaces. The fire-box should 
be arranged with proper grates and draft openings 
to suit the fuel to be used and should be easily 
cleaned. The water spaces should surround the fire- 
box as completely as possible so as to present a large 
heating surface and prevent its plates from over- 
heating. The boiler should be cleaned regularly of 
all mud and settlings left by boiling away the water. 
When using ordinary well water, once a week is often 
enough to clean out. In muddy or alkali water, the 
boiler may require to be emptied oftener than once 
a week. • . — 



CHAPTER VII. 
BOILER FEEDERS. 

ATMOSPHERIC PRESSURE. 

The atmosphere or air surrounding the earth has 
a weight or pressure on the surface of the earth of 
about 15 lbs. per square inch. This pressure varies 
at different heights. Three and one-half miles up 
the pressure is only one-half that at the surface. 
Down in the mines the pressure is greater than at the 
surface. The pressure is everywhere pressing on all 
objects on their lower sides as well as on their upper 
sides and has a tendency to fill all space. Air is 
elastic and when relieved of its pressure it will expand; 
when under pressure it will contract and occupy less 
space; at one-half the pressure it will occupy twice 
the space; at twice the pressure it occupies one-half 
the space. 

As the water in the boiler evaporates or passes off 
in steam, it must be replaced, and this is done by 
devices adapted to force water into the boiler. There 
are two general kinds of boiler feeders in common 
use, pumps and injectors. 

PUMPS. 

Pumps are either self acting, (independent), or 
else they are operated by the piston or crosshead of 
the engine, hence called crosshead pumps. Their 

106 



SCIENCE OF THRESHING. 



107 



main features do not otherwise differ. The essen- 
tial parts consist of a barrel in which a plunger works, 
an inlet valve to the barrel, and an outlet valve. 




The plunger must have an air tight packing around 
it at the end of the barrel which it enters, to exclude 
the air, so that when it is drawn out, the attempt of 
the outer air to get in will force the water in through 
the inlet valve. When the plunger is forced back in, 
the water is pushed out through the outlet valve 
which permits its escape but closes against its return. 
The figure shows a pump having a piston, A , barrel, 
B, inlet valve, C, and outlet valve, D. There is an 
air chamber, E, opening into the pipe beyond the 
outlet valve, so as to relieve anv undue sudden pres- 



IOS SCIENCE OF THRESHING. 

sure in the pipe, while a check valve, F, beyond the 
chamber prevents any back pressure from the boiler. 
A very essential feature of the pump is an air relief 
cock, G, by which the air ahead of the piston and in 
the passages of the pump can be allowed to escape 
when the pump is first started, the cock being kept 
open until water passes out of it. 

When the piston, A, is forced ahead into the bar- 
rel, B, it pushes the water in the barrel out through 
the outlet valve, D. At each stroke of the pump, the 
barrel is alternately filled and emptied, thus imparting 
an intermittent motion to the column of water going 
into the boiler. To partially overcome this starting 
and stopping of the water so suddenly and frequently, 
an air chamber, E, communicating with the feed pipe 
is placed between the pump and the boiler. When 
the water is suddenly forced out of the pump by the 
plunger, a part of it enters the air chamber, com- 
pressing the air; when the plunger reaches the end of 
its stroke and ceases to force the water, the air in the 
air chamber expands and causes the water to continue 
to flow into the boiler after the valve, D, has closed, 
thus lengthening the pulsations of the water and 
acting as a spring or cushion for the water column. 
Care should be taken that the air chamber is tight so 
that the air cannot leak out and spoil the cushioning 
of the water, as it is hard on valves, packing and 
joints of the pump if the plunger is obliged to set the 
whole column of water from the pump to the boiler 
into motion as suddenly as it would do if the air 
cushion were not there. 



SCIENCE OF THRESHING IO9 

Sometimes high speed pumps with long inlet pipes 
work better with an air chamber just outside the 
inlet valve, communicating with the inlet pipe to give 
the column of water flowing into the pump a more 
uniform motion. 

If there is any air admitted to the pump it expands, 
and reduces the vacuum caused by the withdrawal of 
the piston, thereby diminishing the pressure of the 
outer air on the water at the feed pipe mouth, and to 
that extent impeding the inflow of water. If the 
water is too hot, so as to steam, the vapor fills the 
cylinder instead of the fluid, and so interferes with 
its working. 

INJECTORS. 

Injectors make use of a jet of steam to force the 
feed water into the boiler. Although there are 
many makes and kinds, they all work on the same 
general plan. 

The injector consists in general of a suction 
chamber, a condensing tube, and an overflow valve. 
Live steam is taken from the boiler directly through 
a pipe to the injector. As it is forced through the 
condensing tube, it forms a vacuum therein so 
that the water is lifted and enters the condensing 
tube, intermingling with the steam. The water 
being cold, this condenses the steam and greatly re- 
duces its bulk, so that the combined columns of water 
and steam, as thus condensed, are smaller than the 
column of steam alone as it comes from the boiler; 
so there is a less volume or bulk of water entering 



110 SCIENCE OF THRESHING. 

the boiler than there is leaving it in the form of 
steam. The resulting unbalanced pressure thus keeps 
up the circulation and the injector works contin- 
uously. 

All joints should be kept tight to prevent air from 
entering the injector; as air does not condense 
like steam it would prevent the injector from working 
properly. 



CHAPTER VIII. 
BOILER PARTS. 

FUSIBLE PLUGS. 

A very necessary adjunct to the boiler, especially 
in the case of traction engines, is the fusible plug, 
which is placed in the crown sheet to give notice of 
low water. The plug consists of a brass bushing filled 
with an alloy of tin, lead, and bismuth which melts 
at a low temperature. So long as the furnace crown 
is kept well covered with water, its comparatively low 
temperature prevents the plug from melting and it 
remains intact. But the moment that the water gets 
low enough to uncover the top of the plug, it melts 
quickly and the combined water and steam from the 
boiler rushes down on the fire and so reduces the heat 
before the crown sheet is damaged. This fusible 
plug of alloy is inserted in a bushing which is screwed 
home in a hole in the crown sheet. 

GRATES. 

The ordinary type of furnace grate is made of cast 
iron bars which are placed side by side in the furnace. 
The thickness of the lugs cast on the sides of the 
bars determines the width of the air spaces between 
the bars. These spaces admit air to the bed of fuel ; 
consequently the width of the spaces depends upon 
the fuel to be burned and the amount of air it needs. 

in 



112 SCIENCE OF THRESHING. 

For anthracite coal the spaces should be from three- 
eighths of an inch to half an inch wide; while for 
coals that cake much, the width of the spaces may be 
from five-eighths to three-fourths inches. For wood 
or straw the spaces must be still wider. The bars are 
about three-fourths inches wide at the top and taper 
toward the bottom. 

SAFETY VALVE. 

A safety valve is attached to a boiler to prevent the 
steam from rising above working pressure. When 
steam is generated more rapidly than it is used, its 
pressure must of necessity rise, and if no means of 
escape are afforded it, the result must be an explosion. 

The ordinary form of valve used on traction 
engines merely comprises a circular plug or closure 
held to its seat against the outward thrust of the 
steam pressure by a suitably disposed spring. There 
are many different forms, but they all amount to the 
same thing, differing only in their minor details. 

The area of the valve is the area of the opening in 
the valve seat on which the spring pressed valve plug 
rests, or is the projected area of the valve plug sur- 
face which is in direct contact with the steam when 
the valve is closed. The area should be large enough 
to discharge the steam as fast as the boiler will 
generate it, as otherwise the pressure will rise even 
when the valve is open. The following rule is a safe 
one to follow in computing the area necessary for 
the boiler: 

Divide one-half of the number of pounds of steam 
generated per hour by the blow-off pressure increased 



SCIENCE OF THRESHING. 113 

by 10; the result will be the valve area in square 

inches. 

The safety valve should be placed in direct connec- 
tion with the boiler so that there is no possible chance 
of cutting off the communication between them. 

THE STEAM GAUGE. ■ 

The steam gauge indicates the pounds pressure of 
the steam in the boiler. The article is too well known 
to need special mention. 

So far there have been described the device in 
which the steam is generated and a few of the acces- 
sories by which note is kept of the condition of the 
steam and water in its interior. It must not be lost 
sight of that the boiler and its fire-box are but a means 
to transfer the latent heat, that is, the rapid vibrations 
of the molecules of the burning fuel, to the mole- 
cules of the water in the boiler, which tend to cause 
the latter to fly apart and thereby impart motion to 
an engine piston. Remembering this fact, and that 
it means dollars in the pocket of the engine owner 
to have as many of these foot-pounds of energy trans- 
ferred without loss as is possible, it is well to heed the 
following hints. 



CHAPTER IX. 

CARE OF THE BOILER. 

The boiler should be examined carefully to see that 
all the plates exposed to the fire are free from heavy 
scale and not banked with dirt and mud. If the 
boiler be an old one, stay bolts and flat surfaces 
should be examined for breaks and ruptures, and the 
shell should be tested for thin places caused by the 
rusting of the metal, by pounding with a hammer. 
Thin places easily dent under the hammer blows, and 
if they extend over a large section of the boiler it is 
unsafe to run even at a very low pressure. 

The position of the gauge glass should be 
determined so that the engineer may know how much 
water there is on the crown sheet when the gauge 
shows an inch or more. This is easily done by 
removing the hand hole plate at the rear of the boiler 
after the engine is in a level position. Then open 
the valves leading to the gauge glass and fill the 
boiler with water until the crown sheet, which may 
be readily seen, is covered with the depth of water 
required; this may be from two to five inches, 
according to the arrangement of the steam and water 
space. By noting the depth registered in the gauge 
glass when the desired depth is obtained, the engineer 
will have means of knowing just how much water 

114 



SCIENCE OF THRESHING. 115 

there is in his boiler. The position of the engine must 
be taken into consideration also, as he will carry a 
greater depth when the engine is tilted back, so 
causing the water to run up in the gauge, to insure 
that the forward or upper end of the crown sheet be 
covered. Conversely, if the engine be tilted forward, 
he will carry less, as the gauge glass will be at the 
higher end of the crown sheet. If the engine be 
tipped sideways, this must also be taken into account 
to prevent a burned fire- sheet. If the engine be trav- 
eling along the road, good watch will have to be kept, 
as it is difficult to tell, from the agitation of the 
water, just how much there is. In running down a 
steep hill, the water is liable to run forward in the 
boiler and leave the crown sheet bare. Therefore, 
before reaching the crest of the hill, the boiler should 
be filled enough to insure the covering of the crown 
sheet; the fire may also be deadened for a time by 
putting on a layer of fresh coal. 

When steaming up, the boiler should be properly 
filled and a fire started in the fire-box with all the 
drafts open and the spark arrester removed from the 
stack, when possible, as it impedes the draft. When 
using natural draft only, the fuel on the grate should 
be as thin as possible. 

When steam commences to rise, the steam gauge 
should be watched closely to see if the hand com- 
mences to move and indicate the pressure. If it stays 
stationary until a pressure of five to ten pounds is 
obtained, it should be removed and tested, as it is 
inaccurate and not to be relied on. 



I I 6 SCIENCE OF THRESHING. 

When the steam gauge registers fifteen or twenty 
pounds, the blower may be opened, but this should be 
done with caution, as the fierce heat resulting from 
its use is very trying on the parts directly exposed to 

the fire. The heat too will be unequally distributed 
in different parts of the boiler and the result will be 
unequal expansion and consequent leakage and weak- 
ening of joints. The initial or first firing of the 
boiler should be done with care, in order to bring all 
the parts to as even a heat as possible. The average 
sized traction boiler should be allowed from forty- 
five minutes to an hour in which to come to a full 
head of steam. 

Soot and scale are very poor conductors of heat, 
and the fire walls and flues should be kept as free 
from them as possible in order that they may have a 
fair chance to transmit the heat as directly as possible 
to the water. The losses consequent on leaving the 
firewalls lined with dirt amount to a considerable, 
from the extra amount of fuel required to generate 
the heat. 

The boiler should not be blown off when hot, as the 
sudden cooling is as bad as the sudden heating, while 
any scale on the shell and flues hardens and bakes on 
the walls, thereby being removed with difficulty. 

The boiler should be properly jacketed with a 
covering of non-conducting material to prevent loss 
of heat by radiation. 

Inasmuch as the traction engine uses all kinds of 
water, some highly alkaline or soapy, thereby 
foaming, and others highly acid, corroding the plates, 



SCIENCE OF THRESHING. II7 

the boiler should be cleaned frequently and all 
deposits removed. 

When boilers are worked to their fullest capacity, 

and the engine makes a sudden demand for more 
steam, the reducing of the pressure will suddenly 
liberate a large quantity of steam, and the violent 
effort this makes to escape from the surface of the 
water, will cause increased foaming and priming. In 
case the increased roaring in the exhaust gives 
warning of this, the throttle may be closed momen- 
tarily, and then opened again gradually, without 
allowing the engine to lose much headway. 



CHAPTER X. 

FIRING. 

The fire should be kept as regular as possible, 
and this may readily be done by placing the fuel on 
the grate in such a manner as to insure an even fire. 
This may be conveniently done in the following man- 
ner: 

Shovel regularly as possible to the fire-box. 

First, shovelful at left hand, back corner; close 
door and wait. 

Second, shovelful at right hand, back corner; close 
door and wait. 

Third, shovelful at right hand, front corner; close 
door and wait. 

Fourth, shovelful at left hand, front corner; close 
door and wait. 

Fifth, shovelful at right hand, center of box; close 
door and wait. 

Sixth, shovelful at left hand, center of box; close 
door and wait. 

And repeat in same order. Wait the same time 
between each shovelful, so that there is uniform, 
regular adding of fresh fuel. 

A thin fire on the grate is more economical than a 
thick one, as it permits the air to come in contact with 
each part of the burning coal better than if the fuel 
is laid deep on the grate. With a little care in 

118 



SCIENCE OF THRESHING. 119 

watching the fire bed and allowing no places on the 
grate to be bare of burning coal and no part so 
loaded as to prevent air from passing up through the 
grate freely, a fierce and hot fire can be maintained 
with a minimum expenditure of coal. 

The ashes below the grates should be kept cleared 
away and the spaces between the grates open to allow 
free passage of the air. 

Oftentimes the water used deposits lime or like 
substances on the inside of the shell. These cake 
over the heating surface, and as they are not ready 
conductors of heat, the boiler will require more fuel 
than it should in order to generate steam enough. 
Consequently, if the engineer finds that an engine is 
not supplying power enough, he should first find :f 
the boiler and its smoke passages are in proper order. 
In the narrow spaces between the side plates of the 
fire-box and outer shell, scale sometimes accumulates 
to such an extent as to completely fill the interval 
between the plates. The energy of the molecules of 
the burning fuel is largely expended in heating this 
scale and as a consequence the water is not turned to 
steam rapidly enough. 

In order to keep the parts in direct contact with the 
fire from burning out or leaking, the water must be 
kept in the boiler at a level which will cover them. 
The engineer is aided in this by the familiar water 
glass, also by a row of gauge cocks placed one above 
the other. By opening these the depth of the water 
can be readily determined. 

In a traction engine, such as used with a threshing 



120 SCIENCE OF THRESHING. 



outfit the boiler not only has to maintain its form 
against internal stress, but it performs the office of a 
frame on which the engine is mounted, therefore it 
must be strong to withstand this strain as well as the 
steam pressure. 



CHAPTER XL 

THE MECHANISM OF THE STEAM 
ENGINE. 

In the theory of the generation of steam it will be 
remembered that the heat of the burning fuel was but 
the motion (vibrations) of its molecules; that if this 
motion was transferred to the water in the boiler 
(through contact with the sheet and flues) it absorbs 
a portion of the heat, that is, its molecules commence 
to vibrate rapidly until the boiling point is reached, 
at which point it fails to increase in temperature 
though the fire continues to burn. This was because 
a portion of it, the heat, the energy, the work-doing 
power of the molecules, was transferred into giving a 
longer swing to the molecules of the water until they 
lost their power of staying together (their cohesion), 
and separated, forming an elastic, expanding gas 
called steam. The engine is but an instrument for 
transmitting the motion of expanding particles of 
steam into a regular, constant movement which may 
be made to do work, and the better the parts are 
arranged and adjusted with this in view, the more 
and better work it will do. 

THE CYLINDER. 

The usual method of obtaining work from heat is 
to admit the steam from a boiler, where it has been 

121 



122 SCIENCE OF THRESHING. 

generated at high pressure, into one end of a cylinder 
fitted with a piston. The end into which the steam is 
admitted is open to the entrance of the steam from 
the boiler and the other end is open to the atmosphere 
(in the simple engine), so that the piston may move 
freely in that direction. The pressure of the steam 
from the boiler drives the piston to the opened end 
of the cylinder. When the piston has reached that 
end of the cylinder, that end is put in communication 
with the boiler and the other end is opened to the air, 
and the piston returns, driving the used steam out 
before it. When the piston is at that end of the 
stroke, the operation is repeated and the piston is thus 
made to move back and forth indefinitely. 

The piston moves to the right or the left because 
the work doing properties of the steam behind the 
piston are greater than are those of the expanded or 
partially expanded steam, or exhaust steam. This 
means that the vibrations of the molecules of steam 
on the boiler or pressure side of the piston are greater 
than those on the other, or exhaust side. The 
molecules of the former are moving faster than the 
molecules of the latter and thus the difference between 
the energy of the former and that of the latter is just 
equal to doing the work of moving the piston. 

It, is necessary to change the to-and-fro motion of 
the piston to a continuous rotary motion in one direc- 
tion. The usual form of mechanism for accom- 
plishing this is known to engine men as the crank 
motion. 



SCIENCE OF THRESHING. 



123 




A represents the cylinder provided with a piston, 
B, while C is the piston rod. A link or connecting 
rod, D, is jointed or pivoted to the end of another 
link or crank arm, E, the other end of the latter 
being rigidly secured to a shaft, F, which revolves 
in fixed bearings. When the piston, B, is at the end 
of the cylinder farthest from the crank or con- 
necting rod, which is commonly called the head end 
of the cylinder, the piston rod, C, connecting rod D 
and crank E are all in the same straight line. As the 
piston returns to the other end of the cylinder, the 
crank arm is caused to revolve about the end fixed 
to the shaft and so imparts a continuous motion to 
the latter. The parts which move back and forth are 
called the reciprocating parts. The outer end of the 
cylinder or head is called the outboard or cylinder 
end; the other end is called the inboard or crank end. 
If the crank moves in the direction indicated by the 
arrow it is said to run over. If it moves in the other 
way it is said to run under. H is the head end and G 
the crank end of the cylinder; N andNi are the cyl- 



124 SCIENCE OF THRESHING. 

inder heads, through the latter of which runs or slides 
the piston stem or rod. Steam is prevented from 
escaping around the rod by means of a stuffing box, 
K, in which expansive packing is placed and secured 
by the stuffing box head. The piston rod is connected 
at its inner end to the piston head which slides loosely 
in the cylinder, and is provided with expansion 
packing rings, M, which spring out and bear evenly 
around against the cylinder wall and so make a 
steam tight joint. 

Steam is admitted to the cylinder through a supply 
pipe, S, which enters a steam chest, O; from thence 
it passes through steam ports, P } which conduct it to 
each end of the cylinder. The ports are formed in a 
valve seat, Q, on which a slide valve, T, moves back- 
ward and forward through the agency of the valve 
stem, R, which passes out of the steam chest through 
a stuffing box similar to the piston stem box and is 
operated by an eccentric on the main shaft. 

The valve is so arranged as to simultaneously 
cover in one position one of the steam ports and an 
exhaust port, U. There is a steam passage through 
the under side of the valve, so that when the ports 
are so connected, the exhaust steam can escape under 
the valve through the exhaust pipe. Only one steam 
port is open at a time, and this enables the steam to 
get in behind the piston and drive it forward; mean- 
time the valve is shifting, so that the steam is soon 
cut off and as the piston reaches the end of its stroke, 
the opposite port is uncovered and the steam again 
enters behind the piston at the other end. In the 



SCIENCE OF THRESHINC. I 25 

figure the port to the left is being closed while that 
to the right is in communication with the exhaust 
port. After the left port is entirely closed the piston 
will be driven to the end of its stroke by the expan- 
sion of the steam already admitted. 

It will be seen that it is necessary to keep the valve 
seat and face of the valve true, so that the steam may 
not leak through and thus cause a waste. In any 
form of valve used (the one shown is the common 
slide), it is necessary that the valve either move on 
or seat itself on the seat accurately so as to prevent 
loss of power. 

In case a slide valve is used, fashioned as that illus- 
trated, there is a heavy pressure of steam on its upper 
surface. This pressure is often lessened by the shaping 
of the valve so that the steam bears on parts of the 
valve which are on the opposite side to the parts 
above the ports. This, of course, balances in part 
the pressure, as only that part of the valve above the 
port which it is covering and the surrounding valve 
seat is not sustained by an equal and opposite 
pressure. These forms of valve are called "balanced 
valves." In any type of valve it is necessary to lubri- 
cate well, and this is conveniently done by feeding in a 
continuous supply of oil to the steam as it enters the 
steam chest from the boiler. 

The cylinder is somewhat longer than the stroke 
of the piston. The space between the piston head and 
cylinder head when the latter is at the end of its 
stroke is called the clearance; the clearance is bored 
larger than the diameter of the cylinder and is called 



126 SCIENCF OF THRESHING. 

counterbore. The counterbore of the cylinder ends 
is to prevent the formation of shoulders from the 
wear of the piston, and its subsequent pounding, 
which would take place if the cylinder were originally 
of one diameter throughout its length. 

In packing the stuffing boxes, it is desirable that 
the packing be placed as evenly as possible around 
the rods, and the glands be drawn home as evenly as 
possible, so as to prevent undue pressure on either 
side of the rods. Inasmuch as the rod may not run 
exactly true, and is rarely of exactly the same diam- 
eter throughout its length, the packing must be 
elastic. Long usage sometimes glazes and hardens 
the packing; when in this condition, the gland should 
not be forced up as the rod will become cut and there 
will be excessive friction and consequent loss of 
power. 

One side of the crank disc is made heavier than the 
other to counterbalance the weight of the connecting 
rod and reciprocating parts. This is done to prevent 
the vibration which would otherwise take place, 
racking the engine and alternately tightening and 
slacking the drive belt. 

The journals on this part of the engine should 
receive great care and not be allowed to become 
loose from wear and thereby occasion knocking and 
pounding. The pillow block or bearing in which the 
main shaft of the engine runs should be kept suffi- 
ciently tight so that the shaft will run true and also 
to withstand the pressure of the piston and connecting 
rod. The bearing may be tightened by removing a 



SCIENCE OF THRESHING. 



127 



liner and screwing the cap down just hard enough to 
make the shaft run true without causing a great deal 
of friction. 

There are means of taking up the wear in the 
bearing brasses of the crank and wrist pin or crank 
pin, as it is more correctly called. These comprise 
wedges held against the outer side of the brasses by 
encircling straps, and drawn in or out by properly 
arranged screws. The brasses should not be drawn 
so tightly as to heat and cling to the shaft, the 
particles of brass thereby becoming abrading par- 
ticles. 

It must be remembered that taking up the brasses 
in this manner changes the length of the connecting 
rod and makes the clearances at the two ends of 
the cylinder unequal. This must be remedied by the 
insertion of shim or liner plates, or by changing the 
length of the piston rod. 

THE ECCENTRIC. 




Motion is imparted to the slide valve by an eccen- 
tric on the main shaft. This consists of a disc, 9, se- 
cured to the shaft so that its center does not coincide 



128 



SCIENCE OF THRESHING. 



with the shaft center. It therefore follows that this 
center, O, describes a circle around the shaft, and the 
diameter, W , of this circle is the throw of the eccen- 
tric. The eccentric strap, 10, which surrounds it, and 
the eccentric rod, n, will consequently travel back 
and forth a distance equal to this diameter. The 
radius of this circle is the radius of the eccentric. 
The eccentric is in effect a crank and reciprocates the 
valve stem and valve. The connection between the 
eccentric and valve stem may be made in a number of 
ways. 

THE SLIDE VALVE. 




The D-slide valve is the most common of the 
valves used to distribute steam in the engine cylinder. 
A section of such valve is shown in the figure in its 
central position, pp are the steam ports, oo the 
bridges, E the exhaust port, ST the valve seat. The 
flanges of the valve, ab and cd, are seen to be wider 
than the ports which they cover. Of this extra width 
the parts ee are called the outside lap, and the parts 
// the inside lap. F is the valve stem connecting 
with the eccentric. 

As the motion of the valve is given by the eccen- 



SCIENCE OF THRESHING. 



129 



trie, the valve is in mid-position when the radius of 
the eccentric is vertical. When the radius is hori- 




zontal, and extending to the left, the valve is in its 
position nearest the head end of the steam chest. 



13O SCIENCE OF THRESHING. 

There are many varieties of valves; the description 
of the working of one will explain the operation of 
all. 

These figures show in skeleton the disposition of the 
parts when the piston is at the different points of the 
stroke. Of course, in order to give a clear view, the 
comparative dimensions of the parts have been dis- 
torted. 

The parts a, b, c, d, are joints or journals to allow 
the parts to take proper positions in the different 
views. O is the main engine shaft on which the 
crank is secured. 

A shows the position of the crank, piston and valve 
at the beginning of the forward stroke. The valve 
has just started to open the steam port at the head 
end to admit live steam to the cylinder, and has 
uncovered the exhaust port to allow the steam from 
the inboard end of the cylinder to escape through the 
exhaust. 

B illustrates the position of the various parts at the 
end of the first quarter of the revolution. The crank 
is upright, both steam ports are fully uncovered. 
The piston is more than half way along its stroke, on 
account of the angularity of the connecting rod. 

C shows the end of the first half of the revolution 
with the crank at the dead center, the piston at the 
end of its stroke, and the valve covering the head end 
port against live steam, and commencing to open the 
exhaust port at that end, while the port at the inboard 
end is just started to open to the live steam. 



SCIENCE OF THRESHING. 



131 



D is the third quarter of the revolution, the crank 
being at the lowest point, and both inlet and outlet 

ports being wide open. 

E shows the parts at the end of the revolution in 
the same position as at the starting point. 

To compensate for the shortening of the valve 
stem and the eccentric straps from the take up for 
wear, as well as for taking up the crank and shaft 
bearings, it is necessary to set the valve so that it will 
have even throw or travel in relation to the center 
of the engine stroke. 

THE GOVERNOR. 

When an engine is running at a constant speed the 
work done by the steam in the cylinder must just 

equal the resistance over- 
come at the flywheel rim. 
Should the resistance be- 
come less than the work, the 
excess power causes the 
moving parts to move 
faster and faster, and the 
engine "races" or "runs 
away." If, on the con- 
trary, the resistance at the 
flywheel rim is greater than 
the work done in the cyl- 
inder, the engine slows 
down and finally stops. 
The work required of an 
engine does not, of course, 




132 SCIENCE OF THRESHING. 

remain constant, and it is necessary to have some 
means for varying the amount of steam to the 
cylinder automatically to suit the work to be done. 
A device for doing this is called the "governor." 
One type of governor is shown in the figure. 
Two or more controlling weights are so hung 
as to revolve around a stem and to move outwardly 
therefrom under centrifugal force against the ten- 
sion of the springs. The spindle is rotated by a 
pulley and a belt connection or the like from the 
main shaft of the engine. The side motion of the 
balls moves the valve through which the steam 
must pass on its way to the steam chest. This is a 
"balanced valve" so that its closure moves easily. 
It is so connected to the balls by appropriate 
mechanism that the valve admits more steam when 
the balls are turning slowly, as when the engine is 
running slowly, than when the balls are rotating 
rapidly and so moving away from the spindle. 
Thus steam is admitted in proportion to the work 
to be done, as the increase in load and slowing 
down of the engine is met by an increase in the 
steam admitted to the cylinder, while a decrease in 
the load and consequent increase of the engine speed 
is counteracted by the shutting off of the steam. 

SPEED CHANGER. 

Speed changers are now provided for traction en- 
gines which permit of the speed being changed from 
the foot board while the engine is in motion. 



SCIENCE OF THRESHING. 



133 



TRACTION ENGINES. 

The accompanying figure shows the most common 
type of combined engine and boiler. The parts are 
indicated by the reference letters. A, boiler; B, drive 
wheels or traction wheels ; C, front truck wheels ; D, 
bull gear; E, bull pinion; F, main pinion; G, 
steering chain drum; H, steering drum bracket; /, 
steering chain; L, front axle or king bolt bracket; 
My smoke stack; N, extension front or smoke box; 




O, damper; P, damper regulator; Q, smoke box 
door; R, high pressure cylinder; S, low pressure 
cylinder; T, steam supply pipe; u, governor; a, 
cylinder lubricator; b, governor belt; c, crank disc; 
d, connecting rod; e, girder frame; f, crosshead; g, 
piston rod; h, stuffing box; i, crank pin; W ', fly- 
wheel; j, friction shoe; I, whistle; m, safety valve; 
n, reverse lever ; p f throttle valve lever ; q, quadrant ; 
r, steering wheel; ss, injectors; tt, check valves; w, 
water tank; x, draw bar; y, draw bar spring. 



CHAPTER XII. 



SETTING THE VALVE. 



When the engine is turned so that the crank arm, 
piston stem and cylinder are lying in line, as when the 
piston is at the end of its stroke, the engine will not 
turn when the steam is admitted behind the piston, 
as it is pushing directly against the shaft. The 
engine is then said to be on a dead center. Obviously 
there are two dead centers corresponding to the two 
extreme positions of the crank. 

In order to set the valve it is often necessary to 
place the engine on its dead center. A method of 
doing this is explained as follows: 

When the crosshead is very near the end of its 
throw, make a mark b, on one of the guides opposite 
the outer edge of the crosshead. Now turn the engine 




in the direction of the arrow until the outer edge of 
the crosshead again comes in register with the mark, 

134 



SCIENCE OF THRESHING. I 35 

b. While the engine is in this position, take a tram, 
d, or a common pair of dividers, and adjust its scratch 
point at about the height of the center of the crank 
shaft above the floor. Place one end on the floor or 
engine bed and with the scratch point make a mark, e, 
upon the edge of the flywheel. The engine will not 
be on the center exactly; the crank pin will be 
slightly above the center. Turn the engine in the 
direction of the arrow, x, until the edge of the cross- 
head comes even with the mark, b, on the guides. 
•The flywheel will have made nearly a revolution and 
the crank pin be the same distance below the center 
that it was above it. The tram point will now make 
a new mark, e, on the rim. Make a mark on the rim 
midway between the mark e and the mark e ', and then 
turn the engine until the center mark, /, is opposite 
the tram point. The engine is then exactly on its 
dead center. Find the dead center at the opposite 
end in the same way. 

To set the valve, put the engine on its dead center, 
place the valve on its seat and connect it with the 
valve rod; shift the eccentric on the shaft until the 
valve has the required lead. Turn the engine the 
way it is to run, until it is on the other dead center. 
If the lead is the same as at the other end of the 
throw or stroke, the valve is correctly set; if it is not, 
the valve rod must be lengthened or shortened until 
the lead at either end is the same. If now the lead 
be too much, the eccentric may be shifted back on the 
shaft; if too little, it may be shifted ahead. 

If the engine has a reversing gear, the reverse 



136 SCIENCE OF THRESHING. 

lever should be set so as to bring one of the eccentric 
rods in line with the valve stem, and then proceed as 
above directed; then shift the lever and bring the 
other eccentric stem in line, and again set the valve; 
in each instance turn the engine for each setting in 
the way it would normally run when the parts are in 
the position given; this turning the engine in the way 
in which it should go as you set it, accounts for and 
allows for any lost motion in the parts. 

TRACTION GEARING. 

Power is usually transmitted to the drive wheels 
from the main engine shaft through a train of gear- 
ing. This gearing is arranged to suit the form and 
equipment of the engine. It usually consists of a 
friction clutch and a main pinion which are secured 
together and run on the main shaft. This main pinion 
engages an intermediate gear which in turn engages 
a compensating gear. The latter imparts motion to 
a pair of bull gears which are secured to the traction 
wheels, the two gears being connected to the compen- 
sating gear through an intermediate gear. By the 
application of the friction brake the engine is coupled 
to the drive wheels, its motion being greatly reduced 
in passing through the gearing, and thus the engine is 
propelled. The compensating gear allows the two 
traction wheels independent movement so as to follow 
the curves and irregularities of the road, whereby 
there is no slipping of the wheels in turning corners, 
and a consequent loss of power. 



SCIENCE OF THRESHING. 1 37 

THE TRACTION OR DRIVE WHEELS. 

The traction or drive wheels should be of sufficient 
width of tire or tread to give good tractive power. 
They are provided with spuds or lugs to prevent 
slipping and are of a variety of forms. The larger 
the traction wheel in diameter the more easily the 
engine will traverse soft ground. 

A large wheel is less liable to slip and revolve on 
the ground as it has a greater bearing, owing to the 
small angle of contact presented to the front side of 
the wheel. 



CHAPTER XIII. 
WHISTLE SIGNALS. 

I he whistle can lie made to do service if its 
use is rightly understood, but it is very poor practice 
to toot and blow it promiscously without any plan 
or method. Tf all threshennen would adopt and 
use a prescribed code of signals, those connected with 
the machine would soon become accustomed to them 
and understand what they mean. 

The less the whistle is used the better, as it scares 
high spirited horses, excites persons not accustomed 
to it, and attracts the attention of all within hearing 
from their work. This time lost would not be very 
much for one man, but twenty-five or one hundred 
men losing from one-half to noe minute apiece, is an 
item which if multiplied often during the fall's run 
will be of enough magnitude to deserve attention. 

CODE. 

One long continuous sound is given to attract atten- 
tion at such times as in the morning or at noon to 
indicate the working place. 

Two long continuous sounds with a short interval 
between them is to denote the work completed for 
that day or at that place, as the case may be. 

One short sound is to stop. 

138 



SCIENCE OF THRESHINC. I 39 

Two short sounds with a short pause between them, 
to go ahead or commence work. 

Three medium short sounds means to hurry, given 
to indicate to those hauling grain that the machine is 
about to wait for them. 

One long, continuous sound followed by three 
shorter ones is a signal to the waterman that the 
supply of water is about exhausted. 

A continuous succession of short and rapid sounds 
denotes fire or other distress and should be responded 
to by all within hearing of the call. 

No one should ever sound the whistle but the 
engineer, as one unaccustomed to it cannot give the 
proper expression to the sound. 

The stroke of the whistle lever should be full and 
steady, and well timed. The valve should not be 
opened too suddenly, but with a clean and steady pull, 
and should be closed gradually. The spaces between 
the sounds should be well timed and of equal length. 
This will give expression to the sound, pleasing to 
hear. An old thresherman once said he could tell the 
character of the engineer by the way he sounded the 
whistle. 

The tone or pitch of a whistle may be changed by 
screwing the bell up or down. The lower down the 
sharper the tone will be, and more piercing to the 
ears of those near by. When the bell is farther up 
the tone will be of lower pitch and can be heard at 
a greater distance and is not so distressing to those 
near by. When set in a position, it should be left so 
and not changed without good reason, as the people 



140 SCIENCE OF THRESHING. 

in the neighborhood become accustomed to it and can 
distinguish whose machine is giving the signals. 

Whistles are sometimes made in chimes of two or 
more tones that are very pleasing to the ear. 



CHAPTER XIV. 

OPERATING AND HANDLING OF THE 

ENGINE. 

Reference has already been made to the care of 
the boiler, and the engine proper, while at work 
requires as close attention and careful handling. The 
correct water level, uniform fire and constant steam 
pressure are to be maintained, as before stated, and, 
in addition to this, the engine, if on the road, is to 
be guided and kept clear of stumps and like obsta- 
cles. Hills are to be planned for and the fire and 
water arranged and regulated accordingly. The 
temperature in which a traction engine works varies 
from the heat of the southern summer to the intense 
cold of the northern winter, and these facts must be 
taken into account in running the machine and 
keeping it in order. 

STARTING THE ENGINE. 

Before starting the engine, open the cylinder cocks 
and let a little steam into the cylinder by opening the 
throttle slightly; wait until the steam has had time 
to heat the cylinder and drive out the water from the 
condensed steam which always forms when the cylin- 
der is cold. This may form in large quantities, and if 
it gets in between the cylinder head and the piston, its 

141 



142 SCIENCE OF THRESHING. 

resistance, if the engine be started suddenly, throws 
a severe strain on the brasses and connections, and 
may even fracture the cylinder head. 

After the cylinder has been heated up at one end, 
the reverse lever should be thrown over to admit 
steam to the other end. If the engine is a compound, 
the reverse lever should be thrown back and forth a 
few times to warm up the low pressure cylinder. 
After the cylinder has been properly heated, which is 
indicated by steam instead of water issuing from the 
cylinder cock, the throttle may be opened enough to 
cause the engine to start slowly. After it has run 
slowly for a little time, the throttle should be opened 
enough to run it at full speed. 

THE ENGINE ON THE ROAD. 

While traveling on the road, the water should be 
carried as high as practical in the glass to insure the 
covering of the fire-box and the flues, while the engine 
is passing over any irregularities on the road. Before 
starting to ascend long or steep hills, fresh fuel 
should be added to the fire in time for it to become 
thoroughly ignited before the steep portion of the 
hill is reached. Fresh fuel deadens the fire and 
absorbs the heat of the live coals, thus momentarily 
checking the generating of steam. If the hill to be 
ascended is a long or steep one, and the engine has 
a heavy load to draw, the speed of the engine should 
be regulated to run only fast enough to use the 
steam as generated. If the engine is permitted to 
run too fast when loaded, the steam pressure will be 



SCIENCE OF THRESHING. 1 43 

reduced, and as a result, the engine will be stalled, 
and there may be trouble in getting it started again 
while on an incline. The reduction of the steam 
pressure so suddenly while a hot fire is burning is 
very liable to cause foaming or priming, and is also 
hard on the joints and weak portions of the boiler. 
The proper plan is to watch the steam gauge closely 
and keep the speed only fast enough to maintain the 
steam pressure sufficiently high to insure the working 
of the engine. When the engine is working at its 
fullest capacity, the reverse lever may be thrown 
over to the last notch on the quadrant to permit the 
cylinder to be filled with live steam during the great- 
est portion of the stroke possible, and thus prevent 
the engine from becoming stalled. 

In passing down hill, the reverse lever may be 
hooked up near the center. If the hill is so steep 
that the engine has a tendency to increase its 
speed, the throttle should be closed and the engine 
should be reversed; the piston will then cushion 
itself on the air in the cylinder and so retard the speed. 
In case this is not a sufficient check, the throttle may 
be opened slightly to admit a little steam and the 
reverse lever moved to a point where the desired 
speed of the engine will be maintained. 

While on the road it is poor practice to take off the 
governor belt and try to control the speed of the 
engine by the throttle or to run it at a greatly 
increased rate, as the vibration and jar of the oscil- 
lating parts cause strain and undue wear on the 
connecting parts. If it is desired to change the speed, 



144 SCIENCE OF THRESHING. 

it should be done by the governor; this will allow the 
engine to run at the desired speed without fear of 
being run too fast. 

GUIDING THE ENGINE. 

When traveling on the road, the engine is made to 
turn by swinging the front axle as in a wagon, by 
means of the guide wheel and steering chain gear. 
By cramping the wheels more or less, a longer or 
shorter turn is made. 

To find the space required to turn the engine 
around completely, when the front wheels are 
cramped at a given angle or position, set the wheels 
at the required angle and then draw a line on the 
ground beneath and in a line with the front axle, also 
draw a line under and in line with the rear axle. The 
intersection of these lines will be the center of the 
circle in which the engine will travel when the wheels 
are set in a given position and double the distance 
from this center to the engine will be the diameter or 
width of the circle. 

THE FRICTION CLUTCH. 

To set the train of traction gearing in motion, and 
thus start the engine traveling, the flywheel is first 
put in motion and then the friction clutch is thrown 
into engagement with it. The motion of the engine 
shaft is thus transmitted through the clutch and gears 
to the driving wheels. In using the friction clutch, 
care should be taken not to throw it in gear too 
suddenly, as the strain on the gearing and connections 



SCIENCE OF THRESHING. 145 

is very severe. The ordinary traction engine weighs 
from four to twelve tons and to set this great weight 
in motion suddenly puts an enormous load on the 
driving mechanism. 

The engine should be started slowly. The fric- 
tion clutch may be then thrown in gradually until the 
traction gearing is set in motion when the clutch may 
be sent home and the throttle opened sufficiently 
to give full speed to the engine. 

The friction shoes of the clutch should be just tight 
enough to insure proper driving of the engine without 
slipping; if too tight, there is undue strain and wear 
on the parts which come in contact with the wheel. 

SETTING THE ENGINE. 

When setting the engine in line with the separator, 
the flywheel of the engine and drive pulley of the 
separator should be placed in line and near enough to 
each other so that the drive belt, when placed thereon, 
is not too loose. The engine is then started and the 
friction clutch is thrown in for a moment, causing the 
engine to travel backwards and tighten the belt 
sufficiently to drive the separator. The engine is then 
blocked to prevent it from moving ahead when the 
clutch is released, as it would otherwise do, owing 
to the tension of the drive belt. 

GEAR LOCK. 

If a gear lock is on the engine, it should be thrown 
in before the engine is started backwards. 

The engine should be set nearly even or level for 
threshing or other stationary work. The rear end 



146 SCIENCE OF THRESHING. 

should be somewhat lower than the forward; the 
engine should never be inclined the other way, as the 
steam dome is near the forward end of the boiler. 
The elevation of the front end will give a greater 
distance from the steam pipe to the water line; this 
positioning of the engine is perhaps more essential 
in boilers having little steam space than those having 
large space. 



CHAPTER XV. 

TESTS FOR LEAKS. 

The cylinder rings and the valve should be occa- 
sionally tested to see that they are steam tight. 
Should the piston or valve leak very much steam the 
economy or efficiency of the engine will be considera- 
bly lessened. The steam that leaks through, besides 
being wasted, interferes with the free working of the 
engine by choking the ports and exhaust, thus causing 
high back pressure. If an engine is allowed to do 
much leaking the results are far reaching. The ports 
and exhaust being unduly filled, the engine has to do 
more work to overcome the back pressure on the 
piston and this, of course, means that the governor is 
admitting an extra supply of steam to keep up the 
speed. We thus have a double loss — the steam 
leaking through, and the steam used in excess of the 
normal to overcome the resistance. This excess of 
steam calls for an extra amount of feed water to be 
forced into the boiler, an extra amount of fuel to be 
burned, and an extra high temperature to which the 
fire-box and plate are subjected. The engine and 
boiler are thus required to dp an extra amount of 
work, which in some old, worn engines may be nearly 
fifty per cent of the actual work performed. 

The piston and valve may be easily tested as 

147 



148 SCIENCE OF THRESHING. 

follows: Place the engine slightly off the center in 
the direction it is intended to run, a sufficient distance 
to insure the steam port being open to admit the live 
steam to the cylinder; take a strong chain and fasten 
to the rim of the flywheel adjacent to one of its 
spokes, and secure it to some stationary part of the 
engine in such a manner that when the throttle is 
opened, and steam is admitted to the cylinder, the 
flywheel cannot revolve, but resists the pressure of 
the steam on the piston. With the engine in this posi- 
tion and the throttle open, we have full boiler pres- 
sure on one side of the piston and the other side 
exposed to the atmosphere through the exhaust ports 
and pipes. By placing the hand over the exhaust 
nozzle, at the base of the smokestack, any leakage of 
the steam through the cylinder rings or valve seat 
may be easily detected. If much steam is escaping, 
the valve seats and rings should have attention; 
however, the most perfectly fitted engines will leak 
some. 

If the engine is found leaking, the next step is to 
determine whether it is through the valve seat or 
cylinder rings. This may be done as follows. Place 
the engine slightly off the exterior dead center in the 
direction intended to run, which will open the steam 
port at the crank end of the cylinder. Chain the 
flywheel as before and remove the cylinder cap. 
With the engine in this position and the throttle valve 
open, and steam pressure on the valve and on the 
piston in the crank end of the cylinder, the point of 
leakage can be easily detected. If the steam escapes 



SCIENCE OF THRESHING. 149 

from the head end steam port leading to the valve 
seat, it clearly indicates that the valve is leaking; if 
the steam escapes around the piston head, it is plain 
that the cylinder rings are leaking. 

It is a good plan to test the piston and valve in 
different positions, as in some positions they are found 
to leak while in others they are perfectly tight. This 
is owing to the fact that the cylinder does not wear 
evenly. 

In testing, great care should always be taken to 
have the flywheel firmly secured, as play of a few 
inches might break the chain and do injury to the 
operator. 

If the valve is found to be leaking, it may be 
repaired by planing the valve and valve seat, and 
afterwards scraping to a true surface by means of a 
scraper and surface plate. 

If the cylinder rings are found to be leaking, they 
should be expanded or replaced by new ones; cylinder 
rings in pistons which are constructed with an inside 
ring and stud bolts for the purpose of forcing the 
rings outwardly to the wall of the cylinder, are the 
only ones that can be expanded successfully. In other 
forms of pistons and rings where a groove is turned 
in the piston, and the rings are sprung into place and 
held by their own elasticity, the usual practice is to 
replace the rings by new ones. 

In compound engines the same general plan of 
testing the engine may be followed, but it is some- 
times more difficult to locate the exact point of the 
leakage, on account of the multiplicity of the ports 
and working parts. 



CHAPTER XVI. 

FRICTION AND LUBRICATON. 

The rubbing of the surface of one body against 
that of another produces friction. Friction varies 
greatly with different materials, conditions of the 
surfaces in contact and the weight bearing them 
together. The friction between two pieces of pol- 
ished steel is much less than between two pieces of 
brick. 

The power expended in overcoming friction is 
transformed into heat, and the greater the friction 
between two surfaces the greater the quantity of heat 
produced. 

Friction is caused between two surfaces by the 
unevenness and roughness of the surfaces in contact. 
No matter how smooth a journal or box may seem to 
be, the surface is dotted all over with minute points 
or projections, with indentations or depressions 
between them. 

When the two metals of the journal come in 
contact, the points of one of the bodies settle down 
and fit into the depressions of the other, and when the 
bodies are moved in relation to each other the points 
cling fast, and some of them break off, thus wearing 
the surface away. 

By the application of properly shaped particles 

150 



SCIENCE OF THRESHING. I 5 I 

between the points or projections of two contacting 
metals, the pieces may be moved with much less re- 
sistance or friction. Lubricating oils or greases are 
used to supply these particles. The globules of the 
lubricating material tend to hold the surfaces of 
the metals apart, permitting the small projections to 
pass each other without touching, thus reducing the 
friction and wear. The materials best adapted for 
lubricating purposes are those whose globules retain 
their natural shape under the greatest pressure. This 
property of lubricating oils and greases is called 
viscosity. The lubricant in a revolving journal will 
lose its viscosity after a time, and permit the surfaces 
to come in contact; for this reason it is necessary that 
a fresh supply of oil be fed to the journal to replenish 
the old oil. 

The cylinder rings and valve seats require special 
lubricating oil, capable of resisting the heat to which 
the parts are exposed. Cylinder oil should resist a 
temperature much higher than the steam temperature 
before its particles become dissociated or evaporate. 
If cylinder oil is so light or volatile that as soon as 
it is exposed to the high temperature of the steam the 
liquid portion evaporates, leaving a dry, sooty like 
residue, it is valueless as a lubricant and a positive 
injury to the face of a valve or cylinder ring. 

Cylinder oil may be easily tested by putting a small 
quantity on a steam pipe under boiler pressure, whose 
heat is therefore equal to the engine cylinder. If 
the oil boils, smokes or evaporates quickly, it is unfit 
for cylinder lubrication. Put a little oil such as 



152 SCIENCE OF THRESHING. 

kerosene or light machine oil on such a pipe, and see 
how rapidly it evaporates and disappears in smoke 
and gas. 

The cylinder "lubricators" should furnish a con- 
tinuous supply of oil to the engine. This supply 
should be constant although a small quantity will 
suffice to keep the valve and cylinder rings lubricated. 
From three to five drops per minute of best grades of 
cylinder oil will keep the ordinary traction engine well 
lubricated, while with lighter grades, from five to 
seven drops should be used. 

Gearing which has to withstand a heavy pressure 
on the face of its teeth should be lubricated with some 
kind of hard oil or axle grease. 

In recent years hard oil has come into general use 
for journal lubrication. 



CHAPTER XVII. 
WINTER CARE OF THE ENGINE. 

If an engine is not in use it should be stored in a dry 
shed to prevent deterioration caused by rust and 
dampness. It should be cleaned of all dirt. The 
smoke stack and outside of the boiler should have a 
coat of linseed oil to prevent rusting. The inside of 
the boiler should be cleaned, the handhole plates 
should be fastened in again and all valves and con- 
nections kept closed, to exclude air. The boiler will 
not rust or corrode on the inside, if kept air tight. 

The piston rod and valve stem should be coated 
with some non-corroding oil and the engine should be 
left in position with the piston at the end of the back 
stroke; this leaves the piston rod housed in the 
cylinder. The cocks should be kept closed to exclude 
air and prevent rust. 

All pipes and Valves should be well drained to 
guard against bursting or straining by freezing. 

If the boiler has formed much scale on its heating 
surface, the most of it will loosen and drop off during 
the idle season by the unequal expansion of the iron 
and the scale from changes of temperature. The 
loosened scale should be removed from the boiler 
before starting the engine again. 



153 



CHAPTER XVIII. 

SOME SEPARATOR AND 
ENGINE "DONTS." 

Don't use too many concave teeth in dry straw. 

Don't run with loose cylinder teeth. 

Don't try to thresh tough grain with too few 
concave teeth, or with the concave set too low. 

Don't run belts too loose or too tight. 

Don't forget to keep all nuts tight. 

Don't run journals too loose or too tight. 

Don't have too much blast at the back end of the 
sieve. 

Don't have too little blast at the front end of the 
sieve. 

Don't try to do good work with the separator set 
out of level. 

Don't allow the separator to rock back and forth 
while threshing. 

Don't allow pitchers to overcrowd the separator. 

Don't allow the separator to run with too little 
grain. 

Don't use too many sieves. 

Don't return many tailings to the cylinder. 

Don't have too much end play in the cylinder 
boxes. 

SOME ENGINE "D0N'tS." 

Don't carry too deep a fire. 

154 



SCIENCE OF THRESHING. I 55 

Don't allow the ashes to accumulate under the 
grates. 

Don't allow the spaces between the grates to 
become choked with cinders. 

Don't stir the fire enough to cause small particles 
of unburnt coal to fall through the grates. 

Don't allow vacant spaces on the grates. 

Don't have the fuel spread unevenly on the grates. 

Don't allow mud and scale to accumulate on the 
heating surface of the boiler. 

Don't neglect to keep the flues clean from soot. 

Don't pump cold water into the boiler too rapidly. 

Don't run with too low water. 

Don't carry water high enough to cause priming 
or foaming. 

Don't forget to put out your fire if water gets 
below crown sheet. 

Don't forget to drain pipes in freezing weather. 

Don't forget to open the boiler stopcock before 
starting the pump. 

Don't fail to keep your water glass tubes and 
cocks clear and open. 

Don't try to work the pump when the tank is 
empty. 

Don't run the engine with stuffing box glands too 
tight. 

Don't fail to replace old burnt and hard packing 
with new. 

Don't fail to test your piston and valve for leaks. 

Don't run an engine with valve set improperly. 

Don't fail to adjust brasses and journals. 



156 SCIENCE OF THRESHING. 

Don't tinker with valves that are set properly. 

Don't fail to keep all wearing parts well lubri- 
cated. 

Don't fail to keep all other parts clean and free 
from oil. 

Don't run an engine and separator out of line. 

Don't run main drive belt too loose. 

Don't neglect the rig when not in use. 

Don't forget to make the most of your opportu- 
nities. 



CHAPTER XIX. 

A SUGGESTION. 

A Suggestion as to soliciting threshing. Go about 
it in a business-like way. When you meet the man 
that has a job that you want, ask him for it in a plain, 
practical manner. Assure him that you will do him 
a good job in a workmanlike way and save his 
grain, and do it in as short a time as is consistent with 
good work. The subject of price usually comes up 
at this time and this is the best time to lay the founda- 
tion for prompt collections. 

Let your rule be one price to everybody and the 
account cash as soon as work is done, unless there is 
reason for an extension. Be sure to have this under- 
stood at the time, just when and how the account is 
to be paid. This is business and no one ought to take 
offense at it; but if nothing is said and the work is 
done, the parties to the transaction may have entirely 
different ideas as to the price and time of payment. 
This often leads to difficulties that require some 
sacrifice to adjust, and the farmer feeling miffed, will 
resolve to do business with some one else next time, 
all because the start was not made right. 

There is no more reason why a thresherman should 
wait for his money than anyone else. He has his cap- 
ital invested and has to pay his help as he goes along. 

157 



J 5 8 SCIENCE OF THRESHING. 

It is usually the thresherman's own fault if he has 
poor collections, for not being firm and exact. He 
would better lose a job now and then than to lose the 
pay after he has done the work. 



SCIENCE OF THRESHING. 



*59 



TABLE OF THE AREAS AND CIRCUMFERENCES OF 
CIRCLES AND OF THE SIDES OF SQUARES OF THE 
SAME AREA. 





Diam. 
of Circle 

in inches 


0> 

u 

c 

0) <v 

-2 2 

U 


< a 


c 
^S 6 

O nS to 
m 

CO £ 

*d c 

s . % 

c s- 


HI K 

.tjo C 

*-< c 
o ~ 


i 

o 

5 *> 

S- O 

gu 

o 


o O — ' 


c 

w P J, 

R m 

a c- s 

05 <! 


1 


3.14 


.785 


.89 


21 


65.97 


346.36 


18.61 


% 


4.71 


1.767 


1.33 


y 2 


67.54 


363.05 


19.05 


2 


6.28 


3.142 


1.77 


22 


69.11 


380.13 


19.50 


y 


7.85 


4.909 


2.22 


y 2 


70.68 


397.61 


19.94 


3 


9.42 


7.069 


2.66 


23 


72.25 


415.48 


20.38 


y 


10.99 


9.621 


3.10 


y 2 


73.82 


433.74 


20.83 


4 


12.56 


12.566 


3.54 


24 


75.39 


452.39 


21.27 


y 


14.13 


15.904 


3.99 


y 2 


76.96 


471.44 


21.71 


5 


15.90 


19.635 


4.43 


25 


78.54 


490.88 


22.16 


y 


17.27 


23.758 


4.87 


y 2 


80.10 


510.71 


22.60 


6 


18.84 


28.274 


5.32 


26 


81.68 


530.93 


2 3.04 


y 2 


20.42 


33.183 


5.76 


y 2 


83.25 


551.55 


23.49 


7 


21.99 


38.485 


6.20 


27 


84.82 


572.56 


23.93 


y 2 


23.56 


44.179 


6.65 


y 2 


86.39 


593.96 


24.37 


8 


25.13 


50.266 


7.09 


28 


87.96 


615.75 


24.81 


% 


26.70 


56.745 


7.53 


y 


89.53 


637.94 


25.26 


9 


28.27 


63.617 


7.98 


29 


91.10 


660.52 


25.70 


y 


29.84 


70.882 


8.42 


y 


92.67 


683.49 


26.14 


10 


31.41 


7S.540 


8.86 


30 


94.24 


706.86 


26.59 


y 2 


32.98 


86.590 


9.30 


y 2 


95.81 


730.62 


27.03 


ii 


34.55 


95.03 


9.75 


31 


97.38 


754.77 


27.47 


y 2 


36.12 


103.87 


10.19 


y 


9S.96 


779.31 


27.92 


12 


37.69 


113.10 


10.63 


32 


100.5 


804.25 


28.36 


y 2 


39.27 


122.72 


11.08 


y 


102.1 


829.58 


28.80 


13 


40.84 


132.73 


11.52 


33 


103.6 


855.30 


29.25 


y 2 


42.41 


143.14 


11.96 


y 


105.2 


S81.41 


29.69 


14 


4 3.98 


1 53 94 


12.41 


34 


106.8 


907.92 


30.13 


y 2 


45.55 


165.13 


12.85 


y 


108.3 


934.82 


30.57 


15 


47.12 


176.72 


13.29 


35 


109.9 


962.11 


31.02 


y 


48.69 


188.69 


13.74 


y 


111.5 


989.80 


31.46 


16 


50.26 


201.06 


14.18 


36 


113.0 


1017.88 


31.90 


y 2 


51.83 


213.83 


14.62 


y 


114.6 


1046.35 


32.35 


17 


53.40 


226.98 


15.07 


37 


116.2 


1075.21 


32.79 


y 2 


54.97 


240.53 


15.51 


y 


117.8 


1104.47 


33.23 


18 


56.54 


254.47 


15.95 


38 


119.3 


1134.12 


33.68 


y 2 


58.11 


268. SO 


16.40 


y 


120.9 


1164.16 


34.12 


19 


59.69 


283.53 


16.84 


39 


122.5 


1194.59 


34.56 


y 2 


61.26 


•298.65 


17.28 


y 


124.0 


1225.42 


35.01 


20 


62.83 


314.16 


17.72 


40 


125.6 


1256.64 


35.45 


y 


64.40 


330.06 


18.17 


y 


127.2 


1288.25 


35.89 



INDEX. 



PAGE. 

Air — 

Amount of required for combustion 92 

Elasticity of 106 

Ashes 119 

Atmosphere, Pressure of 106 

Babbitt — 

Composition of 68 

Filling boxes with 68 

Pouring 69 

Shimming boxes for 68 

Temperature of 69 

Band Cutters 76 

Barley — 

Adjustment for 50 

Beater — 

Construction of 23 

Office of 23 

Position of 23, 24, 50 

Speed of 24 

Belts — 

Double 66 

Kinds of 64, 65 

Lacing 65, 66 

161 



I 62 SCIENCE OF THRESHING. 

PAGE. 

Operation of 9, 67, 72 

Punch for 65 

Size of punch for 66 

Spacing holes for lacing of 66 

Tension of 52, 64 

Using 64 

Blower — 

Use of 116 

Blast — 

Adjustment of 60 

Angle of 33, 34, 38, 61 

Conditions of 35 

Difference between strength and speed of 57 

Direction of 33, 59 

Law of 36 

Office of 35 

Rule of 56, 57 

Speed of 36 

Strength of 32, 35, 36, 39 

Testing of 59, 60 

Boiler — 

Blowing off 116 

Care of 114 

Classes of 103, 104 

Cleaning 93, 105, 116 

Construction of 1.05 

Definition of 103 

Description of 103 

Jacketing ...116 

Used for engine frame 120 



SCIENCE OF THRESHING. 1 63 

PAGE. 

Boxes of the Shoe 54 

Brasses — 

Adjustment of 127 

British Thermal Unit — 

Definition of 88 

B. T. U.— 

Definition of 88 

Chaffer — 

Operation of ^6 

What it is 33 

Wooden 61 

Check Board — 

Adjustment of 24, 5 1 

Position of 24 

Cleaning Mili 32 

Clearance, Piston 125 

Clutch, Friction 144 

Coal — 

Amount of heat in 88 

Combustion of 91 

Composition of 91 

Theory of combustion 91 

Concave — 

Adjustment of 19, 20, 2 1 , 49, 51, 55 

Construction of 19 

Position of 21 

Teeth of 11, 12 

Crank — 

Description of 123, 129 

Disc .126 



164 SCIENCE OF THRESHING. 

PAGE. 
Motion of 122 

Crew — 

Manager of 74 

Cylinder, Engine 121 

Cylinder, Separator — 

Action of 11 

Adjustment of 15, 48, 55 

As a balance wheel 15 

Backlashing of 23 

Balance of 16 

Boxes of 48 

Construction of 14 

Draft of 22 

How to balance 16, 17 

Power consumed by 44 

Power of 16 

Side play of 18 

Slugging 21 

Speed of 15, 43, 49, 50 

Striking force of 44 

Teeth 15, 4 8 

Dead Center — 

How to find 135 

Dont's — 

Engine 1 . . 154, 1 55- J 5 6 

Separator 1 54 

Eccentric — 

Description of 127, 128 

Motion of 127 



SCIENCE OF THRESHING. 1 65 

PAGE. 

Energy — 

By heat 84, 86 

Engine — 

Adjustment of 71 

Cylinder 121 

Cylinder rings 149, 1 5 1 

Explanation of 121 

Guiding . 144 

Leaking of 147, 148, 149 

On the road 142 

Parts of 123, 124, 133 

Rocking to and fro 52 

Setting 145 

Starting 14 1 

The steam 121 

Traction 133 

Fan — 

Construction of 34 

Operation of 58, 59 

Overblast 35 

Sound of 58 

Underblast 35, 60 

Wear of 59 

Feed Board — 

Position of 22 

Shape of 22 

Feeders — 

The working of 75 

Feeding — 

Plan of 18, 43 



l66 SCIENCE OF THRESHING. 

PAGE. 

Speed of 26 

Uniform 43, 44 

Fire Box — 

Construction of 89 

Firing — 

How done 116, 118 

Firewood — 

Composition of ' 93 

Flail 11 

Flax — 

Adjustment for 49, 63 

Cleaning 62 

Foaming 117 

Foot Pounds — 

Definition of 88 

Equivalent to 88 

Friction 150 

Friction Clutch 144 

Fuel — 

Burning of 89 

Comparative weight and value 94 

Energy of 89 

Extra amount required 116 

Firewood 93 

Straw 94 

( iAUGE 

Glass 114 

Position of 114 

Steam 113 

Watching 115 



SCIENCE OF THRESHING. 1 67 

PAGE. 

Gearing — 

Compensating 136 

Strains on 144 

Traction 136 

Gear Lock § 145 

Getting Ready 71, 72 

Governor — 

Requirements of 131 

Speed changers of . 132 

Grain — 

Cracking 48, 49, 62 

Different kinds 55 

Out of straw 52 

Threshed clean . 48 

Varied conditions of 47 

Wasting 15, 20, 53, 78 

Grates, Furnace . . . . 1 1 1 

Grates, Separator — 

Position of. 21, 50 

Gravitation — 

In separation 28 

Law of 25 

Heat — 

Amount of in coal 88 

Applied to water 85 

Conduction of 93 

Evolved by fuels 92 

Latent 87, 89, 90 

Quantity of .... 88 

Specific 87 



1 68 SCIENCE OF THRESHING. 

PAGE. 

Theory of 83 

Work produced by 83, 84, 89 

Ice — 

Heat to melt 89, 90 

Injector — 

Description of no 

Leaks of no 

Journals — 

Care of 126, 127 

Lace Leather 67 

Leaks, Engine — 

Testing for 147 

Lever, Reverse 143 

Lubrication — 

Cylinder, engine 71 

Hard Oil 71 

Kinds of 70 

Theory of 150, 151 

Machine Frame, Bolts and Nuts 72, 73 

Oats, Separation 49, 50 

Oils — 

Kinds of 152 

Tests for 151 

Operation — - 

Boiler of 115 

Separator 47, 48 

Packing 126 

Piston 122 

Pitchers 76 

Plugs. Fusible in 



SCIENCE OF THRESHING. 169 

PAGE 

Power 49 

Pulleys, Crowned 6 7 

Pumps — 

Kinds of IQ 7 

Leaks IQ 9 

Operation of 107, 108, 109 

Parts of io 7 

Priming 1 1 7 

Rack — 

Combination 3 l 

Forms of 2 7 

Length of stroke 2 9 

Motion of 28 > 2 9 

Raddles — 

Combination of 3 T 

Construction of 3° 

Motion of 3° 

Reverse Lever *43 

Rust 5 1 

Rye, Separating 5 1 

Stackers 4 2 

Safety Valve — 

Area of II2 

Description of II2 

Rules for are I12 

Scale, Effects of 1 16 > 1 19 

Self Feeder — 

Explanation of 44 

Governor for 45 

Office of 45 



170 SCIENCE OF THRESHING. 

PAGE 

Operation of 45, 46 

Power required for 46 

Work of 45 

Separation — 

Aids to 31 

Best methods of 30 

By Gravity 25 

How done 28, 30, 31 

Limit of 26 

Movement of stalks in 25 

Of oats 50 

Process of 25, 26, 50 

Separator — 

Adjustment for dustv grain 51 

Adjustment for rye 51 

Capacity of 26 

Care of 71 

Lubrication of 70 

Parts of 14 

Stands still 17, 51, 52 

Work of . . 13 

Shoe or Cleaning Mill — 

Motion of 53 

Operation of 56, 57 ,61 

Speed of 53 

Sieves — 

Adjustable 33 

Adjustment of 61, 62 

Construction of 32, 33, 34, 35 

Flax 63 



SCIENCE OF THRESHING. 171 

PAGE 

Kinds of 32, 61 

Meshes of 33 

Motion of 32, 34, 37, 38, 39 

Number of 32, 62 

Openings in 34 

Overloading 37 

Variety of 61 

Soot — 

Effects of 116 

Speed Changer 132 

Speed for Rusty Oats .51 

Steam — 

Getting up ... 115 

Heat of 85 

How used 122, 124 

Produced by Heat 85 

Properties of 96 

Saturated 96 

Tables 98, 99, 100 

Straw — 

Action on 20 

Broken 20 

Composition of 94 

Compression of 24 

Chopped 18, 22, 49 

Crew, the 76 

Damp 26 

Dry , 26 

Movement of 28, 30 

Quantity of 29 



172 SCIENCE OF THRESHING. 

PAGE 

Retarding 20 

Travel of 26, 29, 30 

Wedging 21 

With leaves 50 

Stuffing Boxes 126 

Suggestion, A 157, 158 

Tables — 

Circles 159 

Explanation of 101, 102 

Steam 98, 99, 100 

Tailings Elevator 33, 61 

Temperature 84 

Teeth — 

Concave 1 1 , 1 2, 20 

Cylinder 18 

Length of 43 

Loose 18 

New 18 

Number of 20 

Nuts 18, 19 

Space 43 

Testing — 

Cylinder Rings 147, 148 

Piston 147) r 4& 

Valves 147,. 148 

Threshing — 

Ancient method 9, 11, 12 

Kinds of grain 9 

Process of 9, 11, 23 



SCIENCE OF THRESHING. 173 

PAGE 

Traction Wheels — 

Diameter of T 37 

Tool Box — 

Importance of 7 2 

Valves — 

Description of 128, 129, 130 

Keeping True I2 5 

Lubrication of I2 5 

Pressure on I2 5 

Setting 134, 135 

Slide I2 4, i 2 8 

Wagon Loader 4 2 

Wasting Grain — 

Amount of 7®, 79 

Reasons for 5 2 > 53 

Water — 

Changed to steam by heat 9° 

Expansion of by heat 8 5 

In boiler ll 9 

Weather, Influence of 47 

Weighers 4 2 

Wheels, Drive I 37 

Wheat — 

Cleaning weedy ' ° 2 

Spring 55 

Whistle — 

Code of Signals i3 8 > x 39 

How to sound 1 39 

Tone of x 39 

Wind Stacker — 

Horse power required 4°> 4 1 * 4 2 



I?4 SCIENCE OF THRESHING. 

PAGE 

s P e ed of 40, 41, 42 

Weight of air 40 

Weight of straw 4I 

Finis. 



The Parsons and 
Ruth Feeders 

A Pair That Can't be Beat 

ALSO 

SUCCESS ENGINE TENDER 

SUCCESS HUSKER AND SHREDDER 

BUFFALO HAY PRESS 

SUCCESS FARM AND HAY DERRICK 

SUCCESS LIFTING JACKS 

SUCCESSS AUTOMATIC BELT GUIDE 

SUCCESS STRAINER 

SUCCESS CYLINDER WRENCH 

Write us for Catalogue and Prices 

Parsons Band Cutter 

and Self Feeder Co. 

NEWTON, IOWA, U. S. A. 

0*? TT STtfl ■ :< ■■:■■-■■ 



The Gearless Russell 



The Wind Stacker 
that has reduced 
Threshing to a 

SCIENCE 








- 










'^% 


\! 


* f**± W A****. • - - USr ^ 








W*BN 




™lSj 




L.vJ^f^JB 






Mr^fM* 1 



















No Gears 

No Noise 

No Vibration 

No Choking 

Straight Belt 

Takes Least Power 

The Lightest on 

Separation 

We Guarantee it. 



Attached to any make or 

size of Separator at Purchasers 

home without extra cost. 



Russell Wind Stacker Co. 



INDIANAPOLIS, INDIANA. 



\^ 




A Large Majority 

of the Most Successful Threshermen 
USE SOLELY 

Gandy Endless Thresher Belting 

The Strongest as well as the Most Durable Belt Made. Peer 
of all others for out-of-door work. Do not accept imitations as 
being as good. They positively are not. We brand the Gandy 
every ten feet, "GENUINE GANDY BELT." 

SOLE MANUFACTURERS 

The Gandy Belting Company 

BALTIMORE, MD., U. S. A. 



PRESERVO 

Waterproofs Stack and Thresher Covers 

Prevents mildew or rotting in any climate. Will not crack, 
scale, freeze or stick. Old covers painted with PRESERVO 
are made as good as new. Endorsed by U. S. Government and 
used by Barnum & Bailey and all large circus people. 

Don't throw away your old stack covers — patch them and 
paint them with PRESERVO. It will make them better than 
new ones without it. 

Write for booklet and prices. 

W. B. ROBESON, 

MANUFACTURER, 

PORT HURON, - MICHIGAN 



The Famous Sattley 
Attached Stacker 




Is the SIMPLEST Straw 

Stacker Ever Invented 



It attaches to any make of Separator 
and is the most successful attached 
stacker on the market. 



Manufactured 
by 



HEINEKE & CO. 



SPRINGFIELD, ILLINOIS 



THE PORT HURON 1905 RUSHER 

The Malleable Thresher 




The Port Huron Rusher Separator contains 59 Malleable Casting's, not 
counting- those in the Feeder, Bagger and Wind Stacker. 

No other separator equals the Port Huron in strength and durability. 
Aside from the large number of malleable castings, the Port Huron has 
great strength and weight in its hard maple frame, thoroughly supported 
by iron trusses, straps and braces. 

The Port Huron does the best work in threshing* because of its largo 
well proportioned cylinder (not too large) and its large amount of con- 
cave space. ' . .. 

The Port Huron does the best work in separating because of the 
large adjustable grate with fingers through which the grain is driven 
by the beater just after it leaves the cylinder. 

The Port Huron has plenty of separation space on the racks, and this 
space is made effective by the lifting fingers, which thoroughly toss the 
straw about on the lower rack, and the undulations and fishbacks which 
tear the straw into thin sheets on the upper rack. 

The Port Huron does the best work in cleaning because of its side 
shake shoe and adjustable wind guides which direct the blast to every 
part of the sieves. 

THE MALLEABLE FEEDER 

Thirty-eight or about two-thirds of the castings on the Port Huron 
feeder are of malleable iron. • 

The distinctive feature of the Port Huron feeder is the fact that it 
is "bossed" by the separator, instead of bossing the separator. It does 
not slug or choke the cylinder. 

THE RUSHER WIND STACKER 

We were the first among threshing machinery manufacturers to build 
wind stackers. The Rusher wind stacker is the rosult of many years 
experience and does the best work. 

Write Us for Most Complete Books of Specifications. 

PORT HURON ENGINE & THRESHER CO,, ^K^K 6 ™ 

Southwestern-Fort Huron Co., St. Louis, Mo.; Peoria. 111. 
Canadian Fort Huron Company, Winnipeg, Manitoba. 
Northwestern-Fort Huron Co., Minneapolis. Minn.; Fargo, N. D. 
Fort Huron Machinery Co., Des Moines, Iowa. 
Wichita-Fort Huron Thresher Co., Wichita, Kansas. 
FOREIGN TRADE OFFICE, 11 Broadway, New York City. 
Cable Address, "RUSHER." 



Before You (j ET . 
Thresh ^f 



Again 



Find out about 



Wood Bros* 
All Steel 



Feed 



er 



THE MOST POPULAR AND SUC- 
CESSFUL FEEDER IN 
THE WORLD. 

Lasts Longer and Works Better. 



THE 
MOST 
PRACTI- 
CAL 
BAND 
KNIFE 
EVER 
PUT IN 
A 
FEEDER 





A 

Positively 
Automatic 
Variable 
Speed 
Governor. 
Some- 
thing 
Entirely 
New. 



It is the easiest thing in the world to destroy the entire earning capa- 
city of a complete threshing rig by trying to operate with an inferior feeder. 
The Wood Bros. Steel Feeder has stood the test of many years under 
all kinds of conditions and still leads the procession. 

We also make Perfection Engine Tenders and Automatic Engine Coup- 
lers. Write us for information and what you need. 

Wood Bros. 
Steel Self Feeder Co. 



Des Moines, Iowa. 



HARTLEY WEIGHERS 




Take the Grain to the Wagon 
Not the Wagon to the Grain 



Send 
postal card 

to us 
for catalog 
and prices 
on our full 

line 





No shoveling. De- 
livers either side 10 ft. 



The true "Science 
of Threshing" in- 
cludes a Hartley 
Weigher. 



"Dakota Special" 
Delivery 15 ft. 



C.J. HARTLEY CO. 

DECATUR, ILL. 




Bags grain 10 feet 
from the Separator. 




Worth its Weight in Gold 
The Rogers Belt Punch 



THROW THEM AWAY 

You no longer need a hammer and a block of 
wood to punch holes in Belts or leather. The 
Rogers Belt Punch, a little article that can be 
carried in the vest pocket, and which is always 
ready, will punch these holes any size from one- 
sixteenth to three-eighths inch in diameter, and do 
it quickly and do it nicely without any trouble or 
bother. Sent to any address, postage prepaid, 
upon receipt of price 75 Cents, 

Order now and get tbe greatest money saver 
ever manufactured. Money refunded if not 
satisfactory* Address 

THE SATTLEY STACKER CO. 



One half actual size. 



Dept. N. 



INDIANAPOLIS, IND. 




Reliable Supplies 

MOST COMPLETE STOCK 

PROMPT SHIPMENTS 

One of the "Sciences of Threshing" is to have the right 
kind of supplies to keep the machinery going. Don't buy stuff 
that can be bought cheaper than it costs to produce good goods, 
but buy from a reliable house, one that stands behind its goods. 



Our Prices are RigHt — Our Goods 
are Guaranteed. 



BELTING 


OIL 


PACKING 


GREASES 


HOSE 


LUBRICATORS 


LACE LEATHER 


OIL PUMPS 


TANK PUMPS 


LIFTING JACKS 


HEADLIGHTS 


GOVERNORS 


INJECTORS 


WRENCHES 


STEAM PUMPS 


BOILER TOOLS 


SPROCKET CHAIN 


VALVES 


BABBITT 


SAWS, ETC. 



'Write for Supply Catalogue j& 



M. M. Baker & Company 

PEORIA, ILLINOIS 



Harrison and Water Sts. 





Inside Facts for Thinking Threshermen 

ABOUT THE THREE-WAY- CRANK THRESHER. 

FACT 1 — It has steel wheels and steel axles. 

FACT 2 — It has our "No-Shake, No-Sag" frame. 

FACT 3 — Wood parts are made from well seasoned hard maple, white 

oak and yellow poplar. 

the front bolster, and the boxes easily adjusted. 
FACT 4 — The cylinder is instantly leveled by means of screw jacks under 
FACT 5 — It is quickly set and the screw jacks make it stand "solid 

as a rock." 
FACT 6 — The weight of the main drive belt is carried low on the center 

of the front axle, so that the frame will not rack from the dragging 

weight of belt at side of the machine. 
FACT 7 — It has two bearings on the driving end of the cylinder shaft, 

so that the shaft runs smooth and cool, and can't be sprung out of 

line. 
FACT 8 — Its construction is so simple and all parts so light running 

that only three belts are required. (Some others have five to ten belts.) 
FACT 9 — The cylinder has 16 double bars with large outside pulleys, 

that give steady, strong power to all rear parts of the machine. 

This 30-inch cylinder knocks all the grain out of the heads, and 

about 90 per cent of it is separated on the long stretch of grates 

before reaching the racks. 
FACT 10 — Our patent Reversible Tiger Teeth have the right size, weight 

and shape for all threshable grains and seeds. The spring-lock 

washer fastening prevents their getting loose, and they can't turn 

in the bars and don't break. Reversing gives you the equivalent of 

a new set of teeth. 
FACT 11 — Our patent Concave Adjuster gives the easiest, quickest and 

most perfect adjustment of concaves to cylinder. 
FACT 12 — Every part of the thresher is in perfect line, and there are no 

hot boxes or journals to contend with; nothing on which straw 

could wrap, and no forks or pickers to give trouble. 
FACT 13 — The principle of separation from cylinder to weigher is the 

most perfect ever devised. The up-hill circular motion of the straw 

racks does the work, and the grain goes in the sack instead of the 

straw stack. 
FACT 14 — The Three- Way-Crank mechanism is so perfectly balanced that 

it has no dead center, and gives the lightest and quietest separating 

motion you ever saw. It requires no adjusting and gives twice the 

throw of eccentric devices. 
FACT 15 — It has a larger straw space above the racks than any other 

thresher, and the straw moves freely without bunching or carrying 

out grain. 
FACT 16 — Our patent end-shake chaffing riddle and side-shake shoe and 

cleaning riddle prevent wasting on the riddles. 
FACT 17 — It does not waste grain of any kind in any condition if it is 

properly operated, threshes fastest, cleans best, and does not take up 

the thresherman's profits in delays or cost of repairs. 
FACT 18 — It is the result of seventy years' honest effort in the direction 

of perfection, and is several steps ahead of anybody's else best. 
Write for our large catalog which shows all the "Stripes" on the Tiger. 



GARR, SCOTT & CO., 



Richmond, Indiana. 



The New Century 
Sep 



ftVfifflY With gearless and noiseless 
CI I CI 11/ 1 Slower is th e m0S f p er f e ct 

and most profitable Grain 
Separator Saver and Cleaner 




Manufactured solely by the 

Aultman & Taylor 



Machinery Company 



Mansfield, 



Ohio, U. S. A. 



>-» CO 



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Bowsher Feed Mills 



(Sold with or without elevator.) 

Crush ear corn {with or without shucks) and 
Grind every kind of small grain. Also grind 
Kaffir-in-the-head. Have conical shape grind- 
ers Different from all others Can run empty 
without injury. 

LIGHTEST RUNNING 

Best built, most convenient, popular with 
threshermen everywhere. Six Sizes, 2 to 25 
horse power. Highest awards at Chicago, At- 
lanta, Omaha, St. Louis World's Fairs. 

B. N. P. BOWSHER CO. 

South Bend, - Indiana 




MACHINE. 

EXPERTS 

CLAIM 



The Ideal Adjustable Sieve 



ut=i=u SJ3=m=y yyyyi 3=uj p^a=&u4=^=u" 



T-T"E'"r r i! \ rrrl I'ml m-pr- r r, t A ^J^f.jj 



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i^m y^&asaa y sa --o-o q^sxp-i .33-r.i' 




a wonder. Remember 
when using an Ideal 
Adjustable Sieve, you can 
clean all kinds of grain 
and seed to perfection. It 
even takes out all dust 
and fine sediment, and 
leaves the grain perfectly 
clean. The lips extend 
downward at an angle of 
about 45 degrees, direct- 
ing the blast of wind up 
through the openings, thus 
cleaning the grain before 
it strikes the Sieve. The 
pitch of the wind blast is 
never changed when ad- 
justment is made for dif- 
ferent kinds of grain. One- 
third lighter, twice as 
strong, easy to place in 
shoe of machine, and eas- 
ily adjusted. When order- 
ing new machines for 1906, 
be sure and ask for the 
Ideal Adjustable Sieve. 

Write at once for cata- 
log and prices. 



THE PLYMOUTH MANF'G. CO., Plymouth, Ohio, U. S. A. 



WEIGHERS 



C/3 

W 

O 
O 

03 





O 
> 

a 

tn 

C/3 



Hart Grain Weigher Co. 

PEORIA, ILL., U. S. A. 

Write for Catalogue- 



C/5 

W 
X 
O 

w 





DO 
> 

O 

o 

m 



LOADERS 





THE "I. X. L." 

ROTARY SEPARATING 

DEVICE 
SAVES 

ALL THE GRAIN 

The "IXL" is the only attachment of its kind on the market. 
It has passed the experimenta l stage. Thousands have been 
sold. 

When equipped with one of these attachments any separator 
is warranted to save 99 3-4 or more per cent of the threshed 
grain from the straw. We know it wil l do this and after making 
exhaustive tests we find that, in common practice today, the 
average separator wastes too much grain. We have demon- 
strated that what we claim is true and have made tests in a 
scientific manner and the results of these tests prove that we 
have in this attachment something that Saves All the Grain. 

Write today for full information and pattern showing how 
the "IXL" is attached to your machine. 



CAN BE 

ATTACHED 
TO ANY 



SEPARATOR 




ADDRESS 

The Sattley Stacker Co., 

DEP'T "N," INDIANAPOLIS, IND. 



THE TRACTION ENGINE 
CATECHISM 

This is the name of a new book 

It is not only new in date of publication, but entirely new 
in form. 

You probably have traction engine books on your shelves. 

.This is an engine book, but entirely distinct. 

It is compiled brom the "Questions and Answers" depart- 
ment of the Threshermen's Review. 

A careful selection of the most important topics has been 
made, and the various subjects are so carefully classi- 
fied and indexed that every topic is easily accessible. 

The book is cloth bound in the standard manner. 

Nearly every reader of "The Review" is regularly reading 
our "Questions and Answers" and knows their value 
to the engine owner and engineer. 

This book is by far the best reference book for the traction 
engineer on the market. 

Size and style same as "Science of Threshing." 

Price per copy, $1.00. 

Published, and for sale by 

The Threshermen's Review 

St. Joseph, Michigan 




to gas engines. 



A monthly paper of 84 to 100 
pages given entirely to the sub- 
ject of gasoline engines and 
accessories. 

This is one of the greatest, 
growing, power questions of 
the day. Gas engines are per- 
forming wonders and bid fair 
to largely revolutionize the 
present conditions. Keep 
posted. Read Gas Power. 
Find out what there is in and 
It may mean lots to you. $1.00 per year. 



PLAIN GAS ENGINE SENSE 

One hundred and twenty-four pages 
of good, practical, interesting reading 
on the selection, care, operation and 
management, of gas engines. You 
don't have to know about them to 
read it. The book tells you what 
you want and ought to know. Get 
it. Read it. 

SO Cents a Copy. 

Address 

Gas Power Pub. Qo. 

St. Joseph, Michigan. 




MAR 9 1006 



